Parrots feather Biocontrol Project abstract

2015-05-17 15.06.26
Parrots feather (Myriophyllum aquaticum)

In 2015, I completed my first project as a Zoology student, and I am proud to say it is currently being peer reviewed for inclusion in the Biocontrol Science and Technology journal. It has been submitted as a short communication (a shortened version of a scientific paper). In addition to being submitted for peer review, it was also presented at a Scientific Conference earlier in 2016 by my supervisor, Dr Philip Weyl. The abstract for the conference presentation can be found at the link below but for ease of reference, I have included the full abstract below, so that you can read more about the project. I have also attached my final presentation at the end with a collection of pictures that can explain even more clearly exactly how I explored the elements within the study and what my results were.

2015-05-17 15.04.35
Lysathia spp. on growth tip of parrots feather

Abstract from

The effects of water stress on the efficacy of the biological control programme against Myriophyllum aquaticum
Chad Keates, Philip S.R. Weyl, Martin P. Hill
Biological Control Research Group, Department of Zoology and Entomology, Rhodes University, Grahamstown

There are several factors that may influence the efficacy of a biological control programme but one that has received relatively little attention is water stress. The biological control programme against Myriophyllum aquaticum has been extremely successful under most conditions in South Africa. However, field observations suggest that the beetle Lysathia sp. is not as effective in seasonal ponds – where at certain times of the year the weed grows on the banks under water stressed conditions. This study aimed to determine the effect of water stress on the ability of Lysathia sp. to feed and oviposit.

The study was conducted in two phases under controlled conditions. The first phase tested whether the females chose to oviposit on water stressed plants and, secondly, whether the eggs and larvae would survive under water stressed conditions. The study showed  that when given the opportunity, the females chose to oviposit on healthy plants as opposed to water-stressed ones (Z(1,20)= 2.803,P= 0.0054). However, the larvae of Lysathia sp. were able to feed and develop with no significant differences on both water stressed and non-stressed parrots feather (U(1,10)= 11.0 P= 0.834).

This study suggests that Lysathia sp. is capable of developing on water stressed plants but, when given the choice, adult females would rather disperse to another locality where plants are under potentially better conditions. This suggests that biological control on water bodies that have a tendency to dry seasonally may not be as effective as permanent water bodies.

2015-05-10 15.06.15
Experimental setup for feeding experiment

Link to abstract:

Abstract in the 43rd Annual Research Symposium on the management of Biological Invasions

Powerpoint presentation of project:

Keates Zoology Project presentation semester final final

2015-09-10 13.32.38
Experimental setup for oviposition experiment




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