GB2412052A

GB2412052A - Trap and method for trapping wasps

Info

Publication number: GB2412052A
Application number: GB0507792A
Authority: GB
Inventors: Karol Pazik; Edward Pazik
Original assignee: ENTPR CRADLE Ltd; Enterprise Cradle Ltd
Current assignee: ENTPR CRADLE Ltd; Enterprise Cradle Ltd
Priority date: 2001-06-14
Filing date: 2001-06-14
Publication date: 2005-09-21
Anticipated expiration: 2021-06-14
Also published as: GB0507792D0; GB2412053A; GB2412052B; ZA200309502B; GB2376619A; GB2412053B; GB0114492D0; GB0512395D0; GB2412052C; GB2376619B

Abstract

A wasp trap comprises a removable bait chamber 6 for collecting trapped wasps and a self-closing mechanism 34, 36 which prevents wasps escaping from the bait chamber 6 when it is removed from the trap. A lid 10 may also be provided for closing the bait chamber 6 when it has been removed from the trap. The trap may also include a vapour chamber 2 with at least one insect entrance 14, and the bait chamber 6 may be coupled to the vapour chamber 2 at a restriction 20 which controls the movement of insects from the vapour chamber 2 to the bait chamber 6. In use, attractant vapour from a bait source accumulates in the vapour chamber and is released through the entrance. Insects enter the vapour chamber 2 and are maintained in flight within it until they drop down into the collection chamber 6 when tired.

Description

24 1 2052 Trap and Method for Trapping Flying Insects The invention

relates to a trap and a method for trapping flying insects, in particular for trapping wasps, yellowjackets or the like.

Flying insects, including stinging insects such as wasps, are well known to be a nuisance in particular environments.

For example, in soft fruit orchards wasps can cause considerable damage to fruit, rendering it unsaleable. It is clearly desirable in such environments to be able to reduce insect numbers. A variety of methods have been used to try to do this, including the use of pesticides and traps. In order to avoid environmental damage, particularly near human food crops such as fruit, it is desirable to avoid the use of pesticides. A number of trap designs exist but in tests the present inventor has found conventional designs to be unsatisfactory, primarily because they trap insufficient numbers of insects but also in terms of ease and safety of use. :.. I. @ e..

. The invention provides a trap and a method for trapping flying insects as defined in the appended independent .

claims. Preferred or advantageous features of the invention 25 are set out in dependent sub-claims. I.

In its first aspect, the invention thus provides a trap . comprising a vapour chamber, one or more entrances for insects defined in a wall of the vapour chamber, and a bait chamber coupled to the vapour chamber at a restriction. The bait chamber has no insect entrances, except at the restriction, which controls the movement of insects from the vapour chamber to the bait chamber.

In this and other aspects of the invention, the trap advantageously comprises a number of important design features to enhance its effectiveness and ease and safety of 431 85gbl 3 18 April 2005 use. These design features are described below with particular reference to a preferred embodiment of the invention for trapping wasps.

Design Features 1. Vapour Chamber l.l The vapour chamber is preferably a distinct chamber from the bait chamber. The vapour chamber may advantageously be manufactured from a clear plastics material, such as PET (polyethylene terephthalate).

There are three principal functions of this chamber: l.2 The vapour chamber is advantageously designed to maximise the lure of an attractant (bait), which is provided in the bait chamber. In natural light, the vapour chamber behaves as a greenhouse raising internal temperatures within the chamber. This has the effect of pumping out attractant vapour through the ..

., . process of gaseous expansion assisted by convection.

Convection within the vapour chamber is also promoted in a preferred embodiment by having a controlled .

: .. number of entrance flutes (funnels) which are positioned at angles to each other. It is particularly preferred to have four entrance flutes. Increasing A. the number of flutes tends to increase the chance of . wasp escape and reduces the greenhouse effect within the chamber. Reducing the number of flutes tends to reduce the effect of drafts through the chamber dispersing attractant aroma or vapour.

l.3 The vapour chamber is preferably designed to capture and retain wasps. The clear PET plastic encourages the wasps in the chamber to continue to fly against the wall of the chamber in a bid to escape rather than being guided to the entrance points. (In other words, 43185gbl3 18 April 2005 were the chamber to be constructed of opaque or dark or coloured materials, light entering the chamber through the entrance flutes would illuminate an escape route for the wasps.) 1.4 The preferred design of the vapour chamber and the trap may advantageously prevent the immersion of wasps in attractant fluid for as long as possible. The reason for this is that the vapour chamber of the trap provides an environment for wasps from different nests to interact aggressively, and the restriction between the vapour and bait chambers prevents the wasps from leaving the vapour chamber too easily. Wasps from different nests become distressed when in close proximity and release chemical messengers to both warn and call more wasps for assistance. This sociological defence mechanism of the wasps is exploited by the vapour chamber as it promotes prolonged close proximity of the wasps and prolongs the period during which the wasps continue to emit the chemical messengers. Once the wasps are immersed in the -..

attractant (bait), which is usually a liquid then the release of these distress chemical messengers to the atmosphere is inhibited. The vapour chamber therefore advantageously has a tall cylindrical shape, which together with the restriction at the vapour chamber A. exit acts to retain wasps in this chamber for as long as possible. Furthermore, because the vapour chamber is saturated with attractant vapour, once inside the trapped wasps tend to be unable to distinguish where the attractant vapour is coming from, and so are not led to the bait chamber by following an increasing vapour concentration. This is also an important design feature in retaining the wasps for as long as possible within the vapour chamber.

43185gbl3 18 April 2005 1.5 The shape and size of the vapour chamber in the preferred wasp trap have been determined through a significant amount of experimentation. It is important to the efficiency of the wasp trap to have a tall vapour chamber of relatively narrow diameter.

The reason for this is to give wasps trapped in the vapour chamber sufficient freedom of movement to allow for aerial manoeuvres in either attacking or escaping from other wasps also captured within the chamber lo whilst at the same time confining those movements so that the wasps within the trap are maintained in close enough proximity to propagate the distress response.

A tall vapour chamber allows for considerable vertical freedom of flight and this is consistent with the IS flight behaviour of wasps for two reasons: firstly, wasps will drop vertically in a natural defensive manoeuvre to avoid predators or other wasps, and secondly, wasps then fly vertically to escape. A tall vapour chamber therefore advantageously reflects and accommodates this behaviour. Importantly, the tall : design tends to increase the time that a wasp flies in . the vapour chamber before falling into the attractant liquid and also means that the wasps when flying ., :. ,. vertically congregate in the same vicinity.

1.6 The vapour chamber is preferably designed such that . the entrance flutes are sited at a predetermined . distance from the top of the chamber. This is a. a.

important because for the trap to work most efficiently the wasps should have a "flying zone" within the chamber in which to compete and interact with other wasps. The inventor has found that siting the entrance flutes too high up in the chamber results in more wasps escaping. This is believed to be 3s because wasps have a tendency to fly vertically, so that they tend to congregate at the highest part of the chamber.

43185gbl3 18 April 2005 1.7 The width of the vapour chamber may also be affected by the shape of the restriction leading to the bait chamber. For example, in a preferred embodiment the restriction is a downward-sloping frusto-conical funnel, which is preferably sufficiently steep to prevent wasps from having a perch upon which they can rest.

2. Entrance flutes 2.1 The entrance flutes (funnels) are preferably horizontal in orientation or should have only a shallow slope. The reason for this is to facilitate ease of access for the wasps. In particular on a smooth surface, such as a PET surface, wasps are unable to easily negotiate vertically orientated or steeply sloping flutes.

2.2 The flutes are preferably tapered from a wider .

:.: .. entrance to a narrower exit into the vapour chamber.

A. The reason for this is to provide an easy landing platform for the wasps, and easy access into the at.

:.. .. vapour chamber, whilst the narrower exit means that the wasps find it more difficult to escape from the vapour chamber. . .

A. .. 2.3 The size of the flutes in the preferred embodiment for .

trapping wasps is carefully controlled to allow access for both British and European varieties of wasp (both foragers and queens) whilst minimising the size of the escape route.

2.4 The flutes are preferably of a carefully predetermined length to reduced the chance of trapped wasps finding the exit. This length has been determined through experiment and by observing the flight behaviour of 43185gbl3 18 April 2005 trapped wasps. Wasps flying against the walls of the trap periodically rebound from the walls but do so without rebounding by more than a given distance. The flutes are carefully controlled to this length.

Longer flutes prevent rebounding wasps from escaping but disadvantageously reduce the space for flying inside the vapour chamber.

2.5 The flutes are preferably of a number and positioned around the chamber so as to maximise drafts through the chamber to enhance the attractant lure of the trap whilst minimising the incidence of wasp escape and whilst protecting as far as possible the greenhouse conditions within the vapour chamber.

2.6 The flutes are preferably staggered in vertical orientation (vertically spaced) to prevent wasps flying straight through the trap, and to increase the amount of convection within the trap so as to enhance the vaporization of the attractant by continuously removing more vapour from the trap, so reducing the , . vapour density of the attractant in the head space of the trap (i.e. the vapour chamber), so promoting .: ,' further evaporation of attractant.

>:. 25

A

3. Restriction between Vapour Chamber and Bait Chamber A: e ". 3.1 The restriction is preferably designed so as to allow ee a.

wasps that are tired to pass or drop through into the bait chamber but to deter or delay the passage of more energetic wasps into the bait chamber.

Advantageously, the restriction takes the form of a downward-sloping, frusto-conical funnel at the base of the vapour chamber, the bait chamber being positioned below the funnel opening.

43185gbl3 18 April 2005 3.2 Wasps have a natural tendency to fly towards light.

The restriction is preferably manufactured in an opaque material, such as black opaque PET, to guide wasps (which tend to fly towards light) towards the S clear transparent walls of the wasp trap.

Advantageously, both the vapour chamber and the bait chamber have transparent walls. This effectively helps delay the passage of wasps into the bait chamber and also helps to retain wasps in the bait chamber by encouraging them to fly consistently away from the exit (the restriction) towards the clear walls of the bait chamber.

3.3 The restriction is preferably designed to fit IS sealingly into an aperture in a safety plug which fits in an opening at the top of the bait chamber where the bait chamber couples to the vapour chamber. When the vapour chamber is assembled onto the bait chamber the restriction preferably prises or urges open a self closing mechanism, such as a sprung flap. While the a.

vapour chamber is disassembled from the bait chamber, ; . the restriction continues to prevent the escape of wasps from the bait chamber because a seal between the two is maintained until such time as the flap closes.

This is a safety feature of the trap designed to protect the operator from accidental wasp stings. A. ë'

". 3.4 When the restriction is implemented as a funnel, the slope of the funnel is preferably more than 50 , and particularly preferably at least 60 , from the horizontal. This preferably prevents tired wasps from gaining purchase and prevents them from resting and facilitates the eventual passage of wasps into the killing chamber once they have become too tired to continue flying in the vapour chamber. The minimum slope of the funnel may depend on the smoothness of 43185gbl3 18 April 2005 the material from which it is made. A PET funnel preferably has a slope of at least 60 .

3.5 When the restriction is embodied as a funnel, the size of the funnel opening has been assessed through experimentation and it has been found that it is preferably linked to the width of the vapour chamber and slope of the funnel. All of these parameters work together to provide optimum conditions for the efficacy of the wasp trap. If the funnel opening is too large, free falling wasps in defence flight are more prone to fall directly into the attractant liquid. The funnel helps to prevent this in those wasps that are not too tired. Furthermore, if the IS funnel opening is too large, the self closing flap (if fitted) becomes too big and requires larger and more robust closing mechanisms and, more importantly, the required depth of the killing chamber becomes impractically large in order to prevent snagging of the self closing flap on captured and dead wasps once . . the chamber starts to fill. e .

4. Bait Chamber Safety Plug c. e.

4.1 The bait chamber safety plug is a safety feature of the wasp trap of the embodiment, designed to prevent : accidental wasp stings when the bait chamber is being c replaced during re-baiting. The safety plug has a ..

self-closing hinged flap which closes automatically as the vapour chamber is removed.

4.2 The safety plug is preferably manufactured from black opaque PET. In a preferred embodiment, the depth of the safety plug is advantageously lower than an upper shoulder of the bait chamber, in order to retain free flying wasps within the bait chamber by encouraging them to continue to fly towards the light which is 43185gbl3 18 April 2005 maximised in the transparent shoulder of the bait chamber.

5. Bait Chamber 5.1 The bait chamber is preferably manufactured from a clear plastics material, such as PET. This allows visual inspection of the amount of wasps which have been captured and killed.

5.2 The clear design allows examination of the safety flap (if fitted) to ensure that it is unhindered and capable of closing during rebaiting.

5.3 The clear design of the bait chamber advantageously encourages wasps to continue to fly towards the light and away from the opening in the restriction.

5.4 The bait chamber preferably has a line etched onto the wall of the chamber as a guide beyond which it is not .

recommended to capture more wasps. This is a safety feature designed to prevent the self closing flap (if ë fitted) from becoming hindered by the sheer volume of caught wasps.

:. 25 5.5 The bait chamber is preferably square or triangular . . in horizontal cross section and significantly wider . . . than the vapour chamber. This is so that once affixed to the vapour chamber, the baited killing chamber also acts as a counter weight and stable base. This may advantageously allow the trap to be used either free standing or hanging from a support.

6. Bait Chamber Lid 6.1 The lid to the bait chamber may advantageously be designed to screw onto an upper end of the vapour 43185gbl3 18 April 2005 chamber to provide a fixture for hanging the wasp trap. The lid would then preferably be transparent.

6.2 The bait chamber lid is preferably designed to be screwed onto the vapour chamber for safe-keeping whilst the trap is in use. The bait chamber may then be re-lidded when it is ready for replacement and disposal.

7. Mesh Baffle 7.1 The mesh baffle is an optional feature of the wasp trap which when fitted to the restriction, will keep trapped wasps or other insects in the vapour chamber and prevent them from being killed in the bait chamber. This allows the trap to be used as a humane means of capturing insects during field studies where there is no intention or need to kill them.

Description of Specific Embodiments and Best Mode of the ë Invention. I.. .

Specific embodiments of the invention will now be described by way of example, with reference to the drawings in which: : Figure 1 shows a wasp trap according to a first embodiment : . of the invention, assembled for use; I..

J'.

Figure 2 is a partial plan view of the wasp trap of Figure 1; Figure 3 shows the wasp trap of Figure 1 after removal of the bait chamber; and Figure 4 is a reproduction of Figure 3 incorporating dimensions, in centimetres, of a particularly preferred embodiment of the invention.

43185gbl3 18 April 2005 The wasp trap of Figure 1 comprises a vapour chamber 2 coupled at a screw thread 4 to an opening in the top of a bait chamber 6. The vapour chamber is positioned vertically above the bait chamber and the assembled trap can stand on the flat base 8 of the bait chamber. The bait chamber can be unscrewed to remove it from the vapour chamber and can then be sealed using a threaded lid 10. When the bait chamber is coupled to the vapour chamber the lid can be screwed onto a thread at the upper end of the vapour chamber for safe keeping. The lid is also provided with a protruding tab 12 to which a string can be attached, so that the trap may be suspended during use, for example from the branch of a tree.

The vapour chamber 2, the bait chamber 6 and the lid 10 are all advantageously moulded from a transparent plastics material, such as PET. ..

The vapour chamber is circular in cross section as shown in .'. Figure 2, and four insect entrances 14 are formed in its .

vertical side wall. Each entrance is surrounded by a frusto-conical flange 16 which extends into the vapour chamber, ending at a narrow opening 18. The entrances are substantially horizontally oriented so that wasps can easily crawl or fly into the vapour chamber. The length of each . flange is predetermined so that wasps flying within the ..

vapour chamber and rebounding from its walls do not rebound beyond the flanges.

In use, a bait is placed in the bait chamber to release an aroma, which passes into the vapour chamber and out of the insect entrances, to lure insects into the trap. The bait is typically liquid and wasps entering the bait chamber are likely to drown in this liquid.

43185gbl3 18 April 2005 None of the insect entrances are aligned with each other and all four entrances are at different heights. The inventor has found that avoiding alignment of the entrances reduces the number of wasps which escape from the vapour chamber and that vertically spacing the entrances enhances the release of bait aroma from the vapour chamber. In addition, the entrances are circumferentially spaced around the vapour chamber, so that wind from any direction passes through the vapour chamber to distribute bait aroma.

At the lower end of the vapour chamber a restriction 20 comprises a frusto-conical flange, or funnel, 22 extending downwardly from the wall of the vapour chamber to a narrower circular opening 24, from which a cylindrical tube 26 extends into the bait chamber. The restriction is opaque, either being coloured or moulded from an opaque plastics material.

Wasps tend to fly towards light, and in the vapour chamber will therefore tend to fly away from the restriction towards .- upper portions of the vapour chamber. When a wasp is tired, . however, it is desirable that it should enter the bait - .e chamber without delay, and so the angle of the sloping portion of the restriction is chosen to be too steep to . 25 allow wasps to rest on it.

; The bait chamber has a circular opening surrounded by a . cylindrical wall 28, which is externally threaded to engage He either the lower end of the vapour chamber or the bait chamber lid. A safety plug 30 is a push fit within the cylindrical wall and includes a flange 32 which extends radially inwards to a central opening, which fits snugly around an outer surface of the cylindrical tube 26 of the restriction when the bait chamber is threaded onto the vapour chamber. The safety plug also comprises a self- closing flap 34 which is biased by a spring 36 towards a closed position, in which it seals the central opening of 43185gbl3 18 April 2005 the safety plug. As the bait chamber is threaded onto the vapour chamber, an end of the cylindrical tube 26 urges the flap 34 into an open position as shown in Figure 1. As the bait chamber is unscrewed from the vapour chamber, the cylindrical tube is withdrawn, allowing the flap to seal the opening in the safety plug before the bait chamber is fully unscrewed.

Figure 3 shows the bait chamber removed from the vapour chamber, with the flap closing the opening in the safety plug and the bait chamber lid in place.

The safety plug is moulded from an opaque material. Since wasps within the trap tend to fly towards light, this reduces the tendency for wasps to fly out of the bait chamber back into the vapour chamber. It should be noted that transparent shoulders 38 of the bait chamber extend outside and above the bottom of the safety plug. Wasps flying in the bait chamber tend to fly into these shoulders and away from the opening into the vapour chamber. .

. In an alternative embodiment, the trap may be used for A. collecting insects alive. In this case, as illustrated in Figure 3, a cylindrical insert 40 carrying a mesh baffle42 can be pressed into the cylindrical extension 26 of the restriction. The insert is shaped so that the cylindrical I. . tube can still open the flap in the safety plug. However, . the baffle covers the opening between the ...

vapour chamber and the bait chamber so that bait aroma can still be released by the trap but wasps in the vapour chamber cannot enter the bait chamber. Wasps can then be caught alive in the vapour chamber.

Figure 4 is a reproduction of Figure 3 and shows the dimensions of a preferred embodiment of the trap, in centimetres. It also shows the preferred angle for the 43185gbl3 18 April 2005 sloping portion of the restriction 20. Although these dimensions have been found by the inventor to produce a highly effective wasp trap, the skilled person would readily appreciate that the design factors described in this patent application would provide guidance to allow effective traps of different dimensions to be designed, and that such traps therefore fall within the scope of the present invention. : A.

431 85gb13 18 April 2005

Claims

1. A trap for flying insects, comprising; a vapour chamber; an insect entrance defined in a wall of the vapour chamber; and a bait chamber coupled to the vapour chamber at a restriction which controls the movement of insects from the vapour chamber to the bait chamber.

2. A trap according to claim 1, in which the restriction defines an opening through which insects can pass from the vapour chamber to the bait chamber, the area of the opening being smaller than a cross- sectional area of the vapour chamber adjacent the restriction.

3. A trap according to claim 2, in which the area of the ..

opening is less than half, and preferably between 0.25 . and 0.05, of the cross-sectional area of the vapour .e chamber adjacent to the restriction.

4. A trap according to claim 2, in which the opening is substantially circular and has a diameter of between A. ,.. lam and 8cm, preferably between 2cm and 5cm, and . particularly preferably between 2.5cm and 4cm . .

5. A trap according to any preceding claim, in which the restriction is at the bottom of the vapour chamber during use.

6. A trap according to any preceding claim in which the restriction comprises, during use, a surface sloping downwardly towards an opening into the bait chamber.

43185gbl3 18 April 2005

7. A trap according to any preceding claim, in which the restriction is substantially more opaque than a wall of the vapour chamber.

8. A trap according to any preceding claim, in which the wall of the vapour chamber is substantially transparent.

9. A trap according to any preceding claim, in which, during use, the height of the vapour chamber is greater than its width, preferably greater than twice its width, and particularly preferably about three times its width.

10. A trap according to any preceding claim, in which the insect entrance is defined in the wall of the vapour chamber such that, during use, an insect enters the vapour chamber in a substantially horizontal direction.

:.: ,.

11. A trap according to any preceding claim, in which the insect entrance is surrounded by a flange which extends into the vapour chamber from its wall, the flange preferably being frusto-conical, and preferably . 25 having a length equal to or slightly greater than the distance that an insect flying within the vapour ..

.,. chamber typically rebounds on colliding with the wall.

12. A trap according to any preceding claim, comprising a plurality of insect entrances defined in the wall of the vapour chamber, the entrances all being at different heights during use.

13. A trap according to any preceding claim, comprising a plurality of insect entrances defined in the wall of the vapour chamber, none of the entrances being coaxial with each other.

43185gbl3 18 April 2005

14. A trap according to any preceding claim, in which the or each insect entrance is spaced from the top of the vapour chamber during use, to allow space for insects to fly within the vapour chamber above the entrance.

15. A trap according to any preceding claim, in which the or each insect entrance is spaced from the top of the vapour chamber by at least a third of the height of the vapour chamber.

16. A trap according to any preceding claim, in which the bait chamber is detachably coupled to the vapour chamber.

17. A trap according to claim 16, comprising a self closing mechanism for automatically sealing the bait chamber as it is detached from the vapour chamber, in order to prevent insects escaping from the bait chamber. ë -

.

18. A trap according to any preceding claim, in which a wall of the bait chamber is substantially transparent. . .e

19. A trap according to any preceding claim, in which a wall of the bait chamber adjacent to the restriction A. . is transparent.

A ...

20. A trap according to any preceding claim, in which the restriction defines an opening into the bait chamber and, during use, a substantially transparent wall of the bait chamber extends above the level of the opening.

21. A trap according to any preceding claim, in which, during use, the bait chamber is below the vapour chamber and the trap can either stand on a base 43185gbl3 18 Apul2005 portion of the bait chamber or be suspended from an upper portion of the vapour chamber.

22. A trap according to any preceding claim, in which a S baffle can be positioned adjacent the restriction to prevent insects from entering the bait chamber, so that the trap can be used to collect insects alive in the vapour chamber.

23. A bait chamber for a trap as defined in any preceding claim.

24. A method for trapping flying insects comprising the steps of: luring insects through one or more entrances into a vapour chamber containing an aroma emitted by bait in a bait chamber; allowing insects to fly within the vapour chamber; . . -

. restricting the rate at which insects enter the bait - .e chamber from the vapour chamber; and A,

25 trapping or collecting insects in the bait chamber.

. 25. A method according to claim 24, comprising the step of removing the bait chamber to dispose of trapped or collected insects.

26. A method according to claim 24 or 25, in which the step of allowing insects to fly within the vapour chamber causes the insects to emit signals, such as visual, aural or olfactory signals, which attract further insects into the vapour chamber.

27. A trap for flying insects, comprising a removable bait 43185gbl3 18 April 2005 chamber for collecting trapped insects and a self- closing mechanism operable to seal the bait chamber when the bait chamber is removed.

28. A trap for flying insects, comprising a plurality of insect entrances each having an axis defining an insect entrance direction, in which all of the axes are vertically spaced from one another when the trap IS In use.

29. A trap according to claim 28, in which all of the axes are angularly spaced from each other.

30. A trap for flying insects, comprising a chamber in which insects can fly, an insect entrance defined in a wall of the chamber and a flange encircling the entrance and extending into the chamber, in which insects flying in the chamber rebound from the wall and the flange length is equal to or greater than the distance to which insects rebound. .. . . A.

. 31. A trap for flying insects, comprising a chamber and a plurality of horizontal entrances defined in a side : .' wall of the chamber, the chamber having, during use, an upper portion which is transparent and in which insects can fly substantially above the level of the A. ' entrances.

32. A trap for flying insects substantially as described herein, with reference to the drawings.

33. A method for trapping flying insects substantially as described herein, with reference to the drawings.

43185gbl3 18 April 2005 Amendments to the claims have been filed as follows 1. A wasp trap, comprising a removable bait chamber for collecting trapped wasps and a self-closing mechanism operable to prevent wasps escaping the bait chamber when the bait chamber is removed.

2. A wasp trap according to claim 1, additionally comprising; a vapour chamber; and a wasp entrance defined in a wall of the vapour chamber. .... . 15.....

3. A wasp trap according to claim 2, in which the bait chamber is removably coupleable to the vapour chamber at a restriction which controls the movement of wasps. . from the vapour chamber to the bait chamber.

I

4. A wasp trap according to claim 3, in which the . restriction defines an opening through which wasps can pass from the vapour chamber to the bait chamber, the area of the opening being smaller than a cross sectional area of the vapour chamber adjacent the restriction.

5. A wasp trap according to claim 4, in which the area of the opening is less than half of the cross-sectional area of the vapour chamber adjacent to the restriction.

6. A wasp trap according to claim 4 in which the area of the opening is between 0.25 and 0.05 of the cross sectional area of the vapour chamber adjacent to the restriction.

7. A wasp trap according to claim 4, 5 or 6 in which the opening is substantially circular and has a diameter of between lam and 8cm.

8. A wasp trap according to claim 4, 5 or 6 in which the opening is substantially circular and has a diameter of between 2cm and 5cm.

9. A wasp trap according to claim 4, 5 or 6 in which the I() opening is substantially circular and has a diameter of between 2.5cm and 4cm.

10. A wasp trap according to any of claims 3 to 9, in which the restriction is at the bottom of the vapour chamber during use. .... :.

11. A wasp trap according to any of claims 3 to 10 in which the restriction comprises, during use, a surface . sloping downwardly towards an opening into the bait chamber. .e ë: 12. A wasp trap according to any of claims 3 to 11, in which the restriction is substantially more opaque than a wall of the vapour chamber.

13. A wasp trap according to any of claims 2 to 12, in which the wall of the vapour chamber is substantially transparent.

14. A wasp trap according to any of claims 2 to 13, in which, during use, the height of the vapour chamber is greater than its width.

15. A wasp trap according to any of claims 2 to 14, in which the wasp entrance is defined in the wall of the vapour chamber such that, during use, a wasp enters the vapour chamber in a substantially horizontal direction.

16. A wasp trap according to any of claims 2 to 15, in which the insect entrance is surrounded by a flange which extends into the vapour chamber from its wall.

17. A wasp trap according to claim 16, in which the flange is frustoconical.

18. A wasp trap according to any of claims 2 to 17, comprising a plurality of wasp entrances defined in the wall of the vapour chamber, the entrances all being at different heights during use. 15.....

19. A wasp trap according to any of claims 2 to 18, comprising a plurality of wasp entrances defined in the wall of the vapour chamber, none of the entrances , being coaxial with each other. ' .

20. A wasp trap according to any of claims 2 to 19, in which the or each wasp entrance is spaced from the top of the vapour chamber during use, to allow space for wasps to fly within the vapour chamber above the entrance.

21. A wasp trap according to any of claims 2 to 20, in which the or each wasp entrance is spaced from the top of the vapour chamber by at least a third of the 3() height of the vapour chamber.

22. A wasp trap according to any preceding claim, in which a wall of the bait chamber is substantially transparent.

23. A wasp trap according to any of claims 3 to 22, in which a wall of the bait chamber adjacent to the restriction is transparent.

S 24. A wasp trap according to any of claims 3 to 23, in which the restriction defines an opening into the bait chamber and, during use, a substantially transparent wall of the bait chamber extends above the level of the opening.

25. A wasp trap according to any of claims 2 to 24, in winch, during use, the bait chamber is below the vapour chamber and the trap can either stand on a base portion of the bait chamber or be suspended from an upper portion of the vapour chamber. i.

26. A wasp trap according to any preceding claim further comprising a lid for closing the bait chamber when it , , has been removed from the trap. 'a

27 A wasp trap according to any of claims 2 to 25 comprising a lid for closing the bait chamber when it has been removed from the trap, the lid being attachable to the vapour chamber for safe-keeping whilst the trap is in use.

28. A wasp trap according to claim 27 in which the lid provides a fixture for hanging the trap whilst the I trap is in use. I 29. A wasp trap according to any of claims 2 to 28 in I which the bait chamber is coupled to the vapour chamber at a screw thread.

30. A wasp trap according to any preceding claim in which the bait chamber has an opening, a safety plug comprising the self-closing mechanism fitting in the opening.

31 A removable bait chamber for a wasp trap comprising a self-closing mechanism operable to prevent wasps escaping the bait chamber when the bait chamber is removed.

32. A bait chamber according to claim 31 having a wall which is substantially transparent.

33. A bait chamber according to either of claims 31 or 32, comprising a lid for closing the bait chamber when it has been removed from the wasp trap. . 15.e

34. A bait chamber according to claim 33, in which the lid provides a fixture for hanging the wasp trap whilst ' the trap is in use. ,

35. A bait chamber according to any of claims 31 to 34 ',.*,.

having an opening, a safety plug comprising the self- . closing mechanism fitting in the opening.

36. A method for trapping wasps comprising the steps of: luring wasps into a wasp trap having a bait chamber) trapping or collecting wasps in the bait chamber; I 3() removing the bait chamber from the wasp trap; and allowing a self- closing mechanism to operate to prevent wasps from escaping the bait chamber.

37. A method according to claim 36 further comprising the step of rebaiting the wasp trap by disposing of and replacing the bait chamber. IsK

38. A bait chamber substantially as described herein and with reference to the drawings. e''. as..e ce. ate. ë ë ë ë