BIO120 Proposal Draft 2021

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University of Toronto *

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210

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Anthropology

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Dec 6, 2023

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1 Student Number: 1006143718 Lab: Week 1- Thursday 6:00PM TA Name: Casey Carlisle Species Number: 4 Does the number of available perching sites affect the number of preys collected by Libellula pulchella ? Introduction Libellula pulchella are twelve-spotted dragonflies that live largely in North America near bodies of water, i.e., ponds, streams, lakes, etc. These insects are extremely territorial, and aggressively defend their breeding site – typically by males (Pezalla 1979). While defending their territory, they also hunt by waiting for their prey to be vulnerable on water surfaces. Libellula pulchella’s hunting behaviour can be described as hawking. The insects patrol, pursuit, flight, and attack by forming their legs into a claw if threat or prey arrives on their territory (Pezalla 1979). However, all this can only occur with the right perching sites. Their choice of perching sites is dependent on various factors such as: sun exposure, and unobstructed view of territory (Pezalla 1979). Their territorial and hunting behaviour – hawking, can be an adaptive trait for their viability. It is unknown if limited availability of perching sites affects their survival in their environment. Furthermore, the number of available perching sites affect the number of preys collected by the Libellula pulchella , overall affecting their survival. Methods To explore the hypothesis, I will control the number of available perching sites (independent variable) by setting a certain number of branch sites in each environment that is being created. Other controlled variables include the following: gender, type of prey, temperature, no obstruction of view to territory, and time. I will measure the number of preys captured or attacked (dependent variable) by providing an equal number of preys in each environment and then physically counting what is left. To conduct the experiment, I will create a controlled group in a laboratory with five available perching sites (branches attached in various areas in one container) and place a single male Libellula pulchella with 4 mosquitoes and 4 spiders in an environmental temperature of 25 o C (Duong et al 2017). I will place cameras around the container and after 2 days count the number of preys captured or attacked. In an

2 experimental group, I would create 5 different containers with fewer perching sites – container 1 would have 4 branches, container 2 would have 3 branches, container 3 would have 2 branches, container 4 would have 1 branch, and container 5 would have no branches. I will place a single male Libellula pulchella and 4 mosquitoes and 4 spiders in each container with an environmental temperature of 25 o C (Duong et al 2017). I will place cameras around each container and after 2 days count the number of preys captured or attacked. I will then compare the collected statistics to conclude on results. Predications The number of available perching site does not affect the number of preys collected by the Libellula pulchella . If more perching sites were available, the Libellula pulchella will capture more prey, which would lead to the rejection of the null hypothesis. If less perching sites were available, then a smaller number of preys would be collected, which would lead to the rejection of the null hypothesis. If an equal number of preys are collected with more perching sites and less perching sites, then I fail to reject the null hypothesis. Discussion If the results of the experiment reject the null hypothesis, it will indicate that the number of available perching sites does affect the number of preys collected. Hawking behaviour is the only mechanism to capturing food source. This determines their viability for life. For example, in positive correlation, if perching sites are limited in a population due to some environmental factors, competition within the species will increase, and interspecific competition will decrease, leading to a higher possible death rate in the population. This can dramatically decline their survival rate and fitness. If the results of the experiment fails to reject the null hypothesis, it will indicate that the number of perching sites does not affect the number of preys collected. This can indicate an alternate purpose to hawking behaviour, perhaps, mating and reproduction. Patrol, pursuit, and flight can be used for mate selection and dominance in male-male interaction in order to attract female Libellula pulchella .

3 Literature Cited Duong TM, Gomez AB, Sherratt TN. 2017. Response of adult dragonflies to artificial prey of different size and colour. Osorio P, editor. PLOS ONE. 12(6):1-14. Pezalla VM. 1979. Behavioural Ecology of the Dragonfly Libellula pulchella Drury (Odonata: Anisoptera). American Midland Naturalist. 102(1): 1-22.

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BIO120 Proposal Draft 2021

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