Reflex bleeding as anti-predation strategy in ladybirds (Coleoptera: Coccinellidae)

Bishal Kumar Das

Master's thesis

Abstract:

Reflex bleeding or auto-haemorrhaging is one of the many defence mechanism against predator found in insects and in some reptiles. This behaviour is reported widely in several insect taxa, including ladybirds. However, there is a lack of interspecific comparative studies as well as intraspecific comparisons of reflex bleeding reflex behaviour in insects. In this study, reflex bleeding behaviour among several ladybird species was compared by measuring reflex blood volume released while auto-haemorrhaging. Intraspecific effects of sex, live weight and body size on the relative amount of reflex blood were also investigated. The physiological costs associated with the reflex bleeding behaviour were addressed by comparing haemocyte concentration per microliter of haemolymph in control individuals and these forced to repeated reflex bleeding. The significant difference was observed in the reflex bleeding behaviour among the studied ladybird species. Effects of sex and live weight on relative amount of reflex blood released were insignificant, but effect of structural body size was found to be significantly positive. This suggests the efficiency of reflex bleeding behaviour could be higher in species with large individuals. The loss in haemocytes due to repeated reflex bleeding illustrates possible physiological costs of reflex bleeding and probably trade-off associated with reflex bleeding behaviour exists, i.e. ladybirds have to select between actual defence against predators and future efficiency of their immune system.

Keywords

Reflex Bleeding, Auto-haemorrhaging, coccinellidae, interspecific comparison

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 18. 4. 2018

Obhajoba závěrečné práce

• Vedúci: Ing. Michal Knapp, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / odbor:
Engineering Ecology / Nature Conservation