AU2009201042A1

AU2009201042A1 - Larvae traps

Info

Publication number: AU2009201042A1
Application number: AU2009201042A
Authority: AU
Original assignee: Hayter John Edward
Current assignee: Hayter John Edward
Priority date: 2008-03-14
Filing date: 2009-03-16
Publication date: 2009-10-01

Description

-1 LARVAE TRAPS This invention relates to larvae traps. The invention has particular application to mosquito larvae but it may have application in other areas. 5 Certain types of mosquitoes carry disease which, through their bite, they are able to transmit to human beings. Such diseases include Dengue fever, Malaria and Ross River virus. In order to reproduce, the mosquito needs to be able to complete its lifecycle and in order to this, female mosquitoes 10 initially require standing water to lay their eggs. Within 24 to 48 hours of a floating 'raft' of eggs being laid in such water, the egg larvae hatch and for the next 7 to 10 days, the larvae move between the surface to breath and the depth of the water to find food. Afterwards the larvae change to pupa 15 before becoming adult mosquitoes which remain on the surface of the water to dry their wings before flying off. Adult mosquitoes are believed to live for up to two months and it has traditionally been the case in and around populated areas to try to break the life cycle of the mosquito 20 by removing as many (and preferably all) of the forms of standing water from such areas. From a practical standpoint, such traditional methods of mosquito control are almost impossible to guarantee because only a small amount of standing water is required. Therefore, the present invention 25 is aimed at providing an alternative way of breaking the life cycle of the mosquito in populated areas. With the foregoing in view, the present invention resides broadly in a larvae trap comprising a container having a base and one or more walls upwardly extending therefrom to define 30 an open top; and having one or more internal walls downwardly sloping within the container and connected thereto, dividing the interior of the container into first and second compartments, each compartment being in fluid communication -2 with the other by a passage wherein in the container's normal attitude of operation a free end of an internal wall overlies a face of another wall of the container in a spaced apart relationship to define the passage. 5 Preferably the or each internal wall converges. Preferably, the angle of convergence of the or each internal wall is substantially the same. Preferably, the free end of one internal wall extends past another. 10 Preferably, the container is formed from plastics material or glass. Preferably the downward slope of the or each internal wall begins from an internal face of one or more of the walls upwardly extending from the base. 15 Preferably, the container is water tight. Preferably, the or each internal wall is connected to an internal face of one or more of the walls upwardly extending from the base. Preferably the slope of the or each internal wall is 20 linear. Preferably, each compartment is not of equal size. Preferably the or each internal wall is substantially planar. Preferably, the free end of the or each internal wall is 25 the only part of the or each internal wall not connected to an internal face of one or more of the walls upwardly extending from the base. More preferably, the or each internal wall is integrally connected to an internal face of one or more of the walls 30 upwardly extending from the base. Preferably, the arrangement between the passage and the walls of the container are such that a fluid moving from the upper compartment to the lower compartment and onto the base -3 of the container has to undergo more than one change in direction. In order that the invention may be more clearly understood and put into practical effect, reference will now 5 be made to the accompanying drawings wherein: Fig. 1 is a pictorial representation of a larvae trap according to the invention from one end, one side and from above; Fig. 2 is an end elevation of the larvae trap of Fig. 1. 10 The larvae trap 10 shown in the drawings is in its normal attitude of operation and is constructed from clear polypropylene. The watertight trap 10 has an oblong base 11 with four side walls 12 of equal height upwardly extending therefrom to define an open top. 15 Downwardly sloping within the container are a pair of converging internal walls 13 that divide the container into a pair of compartments, an upper compartment 14 and a lower compartment 15. Each compartment is in fluid communication with each other by a passage 16, the passage in the 20 container's normal attitude of operation being defined by a free end of an internal wall overlying a face of another internal wall of the container in a spaced apart relationship as one of the internal walls extends past the other. Each internal wall is made from planar polypropylene 25 (although it could be made from glass) and is integrally connected to three internal faces 17 of the container, the end of one of the internal walls extending past the other and the angle e of convergence for each internal wall being 45 degrees. Such an arrangement leads to the compartments so 30 formed being of unequal size, the upper compartment being generally smaller than the lower compartment. In use, the container is almost completely filled with water to provide a source of standing water and is left in an -4 area where evaporation of the water from the container will be minimal but ideally where mosquitoes are likely to frequent. If a female mosquito 18 lays eggs 19 on the surface of the water 20, the life cycle of the mosquito can begin. Larvae 21 5 in the upper compartment, on account of the sloping sides will tend to traveling downwards through the passage 16 to look for food and will enter the larger lower compartment. Given the staggered overlying arrangement of the internal walls, as the larvae attempt to substantially vertically rise to the surface 10 to breath (a vertical motion being the quickest way to the surface), the larvae find themselves trapped within the lower compartment as vertical travel makes them unable to make their way back through the passage. Instead they will find themselves riding up one of the lower faces of an internal 15 wall. As time passes, they will die in the lower compartment.

Claims

1. A larvae trap comprising a container having a base and one or more walls upwardly extending therefrom to define an 5 open top; and having one or more internal walls downwardly sloping within the container and connected thereto, dividing the interior of the container into first and second compartments, each compartment being in fluid communication with the other by a passage wherein in the container's normal 0 attitude of operation a free end of an internal wall overlies a face of another wall of the container in a spaced apart relationship to define the passage.

2. A larvae trap according to Claim 1, wherein the or 5 each internal wall converges at an angle of convergence substantially the same for the or each wall.

3. A larvae trap according to Claim 1 or Claim 2, wherein the free end of one internal wall extends past another. 0

4. A larvae trap according to any one of the preceding claims wherein the downward slope of the or each internal wall begins from an internal face of one or more of the walls upwardly extending from the base. 25

5. A larvae trap according to any one of the preceding claims, wherein the or each internal wall is connected to an internal face of one or more of the walls upwardly extending from the base. 30

6. A larvae trap according to any one of the preceding claims, wherein the free end of the or each internal wall is the only part of the or each internal wall not connected to an -6 internal face of one or more of the walls upwardly extending from the base.

7. A larvae trap according to Claim 6, wherein the or 5 each internal wall is integrally connected to an internal face of one or more of the walls upwardly extending from the base.

8. A larvae trap according to any one of the preceding claims, wherein the arrangement between the passage and the 0 walls of the container is such that a fluid moving from the upper compartment to the lower compartment and onto the base of the container has to undergo more than one change in direction. 5 Dated this 16th day of March, 2009 John Edward Hayter By his Patent Attorneys AHEARN FOX 0o