Phenotypic variation

Phenotypic variation in introduced species using ladybirds as a model system

Species are introduced around the world and only few species thrive in introduced habitats while some species struggle to survive in the new environments. In my PhD project, under the guidance of my supervisory panel - Dr Anne Wignall, Dr Rich Leschen and Prof James Dale, I assess & compare the level of variation between native and introduced species using ladybirds (Coloeptera: Coccinellidae) as a model system.

Variation in behaviour

Having a high level of variation in functionally important traits such as dispersal ability may increase the establishment success of introduced species. I compared inter- and intraspecific variation in activity levels and responses to a simulated predator attack in four introduced ladybird species. Activity levels and the ability to withstand disturbances are major determinants of dispersal ability as they correlate with how fast and far a species can move. Therefore, variation in activity levels and the ability to withstand disturbances can provide useful insights into a species’ establishment ability.

Here I discuss how dispersal can help predict establishment success and the potential for range expansion in introduced species. More about the findings of this experiment will be available soon!

Variation in morphology

In this study I investigate how body size, wing shape and colour variation differ between five introduced and five native species of ladybird in New Zealand. This study improves our understanding of the biology of introduced and native ladybirds in New Zealand, comprising the first detailed morphometric analyses of these species. It also provides a foundation for future research on the introduction, general biology and ecology of ladybirds.

Our paper is under review at Journal of Zoology!

This graph represents the 3D plot I used to calculate the level of variation in colour in ladybirds.

Hind wing features are associated with dispersal, migration and foraging behaviour. The proximal and distal parts of the hind wings function as separate functional modules at the R-M loop and evolution of the R-M loop influences the efficiency of wing folding in beetles. Wing shape was analysed using geometric morphometric analysis of the right hind wings. There was no difference in the level of variation in wing shape between species, however, I found out that E. vigintioctopunctata had significantly longer MP₁ veins than I. galbula and R. forestieri.

Variation in desiccation resistance

In this experiment I compare desiccation resistance between three introduced species of ladybird. Physiological hardiness (i.e. desiccation resistance and cold tolerance) and its variation may influence establishment success as physiological hardiness is associated with species richness, abundance, and dispersal. Understanding desiccation resistance can help predict the invasive potential of ladybirds.

More about the findings of this experiment will be available soon!

Investigating the association between habitat type and body size of tiger beetles using Artificial Neural Networks (ANN)

Species specificity to habitat types are associated with their preference for oviposition site, prey choice, predator evasion, tolerance to flooding and inundation, climate and soil conditions of the environment. Therefore, tiger beetles are considered as important bioindicators. My undergraduate research was carried out to investigate the association between habitat type and body size of tiger beetles. I analysed morphological data of tiger beetles (Coleoptera, Cicindelidae) and habitat parameters such as soil type, relative humidity, solar radiation, wind speed etc.., to develop a tool to predict the relationship between body size and habitat type of tiger beetles using Artificial neural networks.