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Group 6
<html><font size=6 face=“Arial”>Born to be thief: sundews' prey stealing by flower fly larvae</font></html>
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Introduction
Although little is known about the biology of Toxomerus basalis, a species of flower fly (Syrphidae), a recent discovery helped to elucidate it's habits at the larval stage. Larvae of T. basalis were found feeding on prey captured by the traps of some sundews (Drosera spp.), a genus of carnivorous plants which catch it's prey by secreting a sticky substance called mucilage. As the larvae have been observed to move freely through the sticky traps, they are thought to have adaptations which prevent them from becoming trapped and also from being affected by the digestive enzymes of the sundews.
This constitutes a kleptoparasitic interaction: when individuals of one species steal food from the other species. Although difficult to quantify, this interaction may affect negatively the sundews, diminishing it's reproductive potential or maybe killing individuals.
On the other side, syrphid larvae are known to have low dispersal capacity, making the choice of oviposition location of great importance. Although T. basalis females have not been observed during oviposition, it is thought that they land directly on the sundews to deposit their eggs, making them vulnerable to getting stuck on the sticky traps.
Assignment
Build a mathematical model that incorporates the effects of the kleptoparasitism by the larvae and the carnivory of flies by the sundews.
Questions & Suggestions
- How much susceptible to the lack of nutrients from prey need the sundews be for the kleptoparasitism to affect its population?
- How does the retention capacity of the sundews' mucilage affects the system? On the one side, a strong retention means more prey for the larvae to steal, while at the same time it means more adult flies getting caught.
- How does the theft intensity, either by the population size of the flies or by the stealing efficiency of the larvae, affects the system? How it relates to the susceptibility and the retention capacity of the sundews?
Challenge
- What if the adult flies also act as pollinators?
References
Fleischmann, A., Rivadavia, F., Gonella, P. M., Pérez-Bañón, C., Mengual, X., & Rojo, S. (2016). Where is my food? Brazilian flower fly steals prey from carnivorous sundews in a newly discovered plant-animal interaction. PloS one, 11(5), e0153900.