Impact of Alternate Prey on the Prey Preference, Prey Switch Strategy and Predatory Performance of the water stick insect Ranatra filiformis Fabricius 1790 (Hemiptera: Nepidae)

Author: Subramanian Arivoli, Samuel Tennyson, Miriam Cecilia Vassou, Grace Marin, Raja Kalaivani and Elangovan Vigneshkumar

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Abstract

The present work centers on the hypothesis of whether a predator can switch from one prey to another in a mixed prey population. The present endeavor is to clarify the same using nymphal stages of the water stick insect Ranatra filiformis with the prey species comprising of Culex and Chironomous larvae as a mixed prey population. To investigate the test hypothesis of this study, as well as density-dependent predation of Ranatra filiformis nymphs, this experiment was designed. Ranatra filiformis nymphal stages first and second, and from third to fifth were categorized as ‘small and large predators’, respectively. The nymphal predators were divided into four densities, viz., 4, 8, 12 and 16. The effectiveness of predation was investigated at prey densities of 50, 100, 150, and 200 of both Culex and Chironomous larvae. The first and second instar of the prey were categorized as ‘small prey’, while their third and fourth instar as ‘large prey’. Four experimental design (ED) were set up to study predator-prey interaction, viz., ED1 (small predator and small prey), ED2 (small predator and large prey), ED3 (large predator and small prey), and ED4 (large predator and large prey). Each predator density of each experimental design were introduced into a single container with one litre of dechlorinated tap water, and was offered the above mentioned prey densities with an equal ratio of mixed prey population of Culex and Chironomous. The number of prey fed in ED1, ED2, ED3 and ED4 were noted after one hour and thereafter 24 hours. Overall, in ED1, Chironomous was preferred after one hour, and both Culex and Chironomous after 24 hours, and in general, small predators preferred Chironomous; in ED2, Chironomous was preferred after one hour, and Culex after 24 hours, and in general, small predators preferred Culex and Chironomous; in ED3, Chironomous was preferred after one hour, and Culex after 24 hours, and in general, large predators preferred both Culex and Chironomous; and in ED4, in general, large predators preferred Chironomous. When prey density was increased, predation by small predators was more pronounced in 24 hours, and by larger predators on small prey it fluctuated slightly after one hour, but increased predation was observed after 24 hours; and in the case of larger prey, predation fluctuated after one hour, but after 24 hours, a steady increased predation was observed. Secondly, the small and large predators preferred Chironomous after one hour, and both Culex and Chironomous after 24 hours. Thirdly, maximum predation by the small predators on small prey was at 150 and 200 prey density after one and 24 hours, respectively. In the case of small predators on large prey, and for large predators on small prey it was at 200 prey density for both one and 24 hours. Whereas, for large predators on large prey, it was at 100 and 200 prey density after one and 24 hours, respectively. The current investigation explained about the scenario of the predatory performance, as well as prey preference and prey switch by Ranatra filiformis nymphs in a mixed prey population.

Keywords

Ranatra filiformis, Culex, Chironomous, predator-prey relationship, predatory performance, predator density, prey density, prey preference, prey switch

Conclusion

The current investigation clearly explained about the scenario of the predatory performance as well as prey preference and prey switch by the nymphal stages of Ranatra filiformis in a mixed prey population.

References

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How to cite this article

Subramanian Arivoli, Samuel Tennyson, Miriam Cecilia Vassou, Grace Marin, Raja Kalaivani and Elangovan Vigneshkumar (2023). Impact of Alternate Prey on the Prey Preference, Prey Switch Strategy and Predatory Performance of the water stick insect Ranatra filiformis Fabricius 1790 (Hemiptera: Nepidae). Biological Forum – An International Journal, 15(2): 861-870.