Evolutionary Biology Lab

Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales


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Study organism pages

Neriid flies

Antler flies

Walzing flies

Some current projects

● Nongenetic inheritance in ecology and evolution

In violation of classic assumptions of evolutionary genetics, some nongenetic variation (including some effects of the environment) can be transmitted across generations. Our goal is to understand the ecological and evolutionary role of such effects, collectively known as nongenetic inheritance.

In the neriid fly Telostylinus angusticollis, we have found that both maternal and paternal larval diet affect the morphology and life history of offspring. For example, the nutrient concentration in a male's larval diet can affect the body size of his offspring, and even the body size of offspring sired by another male that mates two weeks later with the same female. We have also found that such effects can depend on the parental social environment.

We are currently using the powerful "nutritional geometry" framework to investigate such effects across the macronutrient space, and directly compare maternal and paternal effects.

We are also exploring the epigenetic mechanisms that mediate paternal effects in this species.

Likewise, we have found that maternal and paternal larval diet can affect offspring traits in the cosmopolitan bruchid beetle Callosobruchus maculatus. Intriguingly, such effects can act in opposite ways on male and female offspring in this species.

In collaboration with Troy Day (Queen's University), we are developing theory on the potential for nongenetic inheritance to influence adaptation and sexual coevolution.

Male neriid flies competing for a female (bottom right) on a tree trunk.

 

T. angusticollis spermatozoon. In this species, the father's larval diet can influence the growth and development of his offspring via factors transmitted in the seminal fluid and perhaps the sperm.

● Dietary ecology and developmental plasticity

Diet can have huge effects on development and thereby influence many important traits, including lifespan and ageing, secondary sexual traits and sexual dimorphism, and many aspects of behaviour.  

In the Australian neriid fly Telostylinus angusticollis, we have found that sexual dimorphism in body size and shape is largely determined by larval nutrition. Moreover, research using the "nutritional geometry" framework has revealed that exaggeration of the male secondary sexual traits (head and antenna, which are used as weapons and signals) depends on the amount of dietary protein available to larvae. Larval and adult nutrition, as well as the social environment, also affect adult reproductive performance, lifespan and ageing.

In addition, we have found that reaction norms for body shape have diversified among populations in the Australian neriid flies (Telostylinus angusticollis and T. lineolatus) and, interestingly, the sexes appear to have diversified in different ways.

Neriid males feeding on acacia bark.

● Sexual conflict and the evolution of facultative sex

Can sexual conflict explain the near-ubiquity of sexual reproduction, despite the costs of sex?

In the Australian Giant Spiny Leaf Insect Extatosoma tiaratum, and several other species of stick insects, females can reproduce asexually (producing all-female broods), or mate and produce offspring of both sexes. We have found that, at least in some circumstances, sexual conflict can favour parthenogenetic reproduction. However, sexual conflict might also prevent sexual populations from evolving a capacity for parthenogenesis, and thereby contribute to the maintenance of sex.

Spiny leaf insect female.

 

● Diet and fitness in wild antler flies

In collaboration with Howard Rundle (University of Ottawa), Brian Mautz (Uppsala University) and Nicolas Rode (INRA, Montpellier), we are investigating the effects of environment (including diet) on life history and performance in wild antler flies -- a tiny Canadian piophilid fly that breeds exclusively on discarded antlers of moose and deer.

Although antler flies are only 2 mm long, their remarkable site fidelity males it possible to mark flies with individual codes, observe them throughout their lives in the wild, and construct individual biographies for them. This species has provided the first evidence of ageing in wild insects, and has revealed that ageing can affect sexual selection. 

 

 

 

 

 

 

 

 

 

 

 

 

  

Marked antler fly males competing for a female.


Current collaborators

Margo Adler (Hobart, Tasmania)

Liran Carmel (The Hebrew University)

Steve Chenoweth (University of Queensland)

Angela Crean (University of Sydney)

Jennifer Cropley (UNSW/Victor Chang)

Troy Day (Queen's University)

Damian Dowling (Monash University)

Mark Greco (Charles Sturt University)

Alexei Maklakov (Uppsala University)

Brian Mautz (Uppsala University)

David Punzalan (University of Toronto)

Nicolas Rode (INRA, Montpellier)

Locke Rowe (University of Toronto)

Howard Rundle (University of Ottawa)

Catherine Suter (UNSW/Victor Chang)

Torsten Thomas (UNSW)