1. MEASURE FOR MEASURE: FEMALE REPRODUCTIVE PLASTICITY
Individuals that respond to their social and sexual
environments gain substantial fitness benefits. Males of many species can
detect cues that indicate they are at increased risk of sperm competition.
Responses include competing more strongly for matings, mating for longer and
transferring more ejaculate components and / or sperm.
However, little is known about the consequences
for females of responding directly to the intra- or inter-sexual competitive
environment. Nor is it known what are the consequences of indirect responses by
females of mating with responding / non-responding males. Females are expected to gain benefits from responding adaptively to
cues that indicate the likelihood of remating, potential cost of each mating,
expected ‘per mating’ investment. These responses are expected to include
effects on future generations via the transmission of ‘competition’
information to offspring in a form that
allows adaptive responses by one or both sexes.
The fitness outcomes of plastic interactions of both mating
partners has been subject to limited theory, but as yet no empirical study.
Plasticity expressed by either one or both parties is expected to maximise
fitness when there is no sexual conflict. Our prediction, under conflict, is
that the fitness benefit for the plasticity-expressing sex is diminished when
their partner is also plastic.
Using the well-characterised genetics of the fruitfly model system and powerful
genetic isoline resources we are conducting a NERC-funded project to conduct hypothesis-driven tests of the
significance of the expression of socio-sexual plasticity in females.
2. FUNCTIONAL SIGNIFICANCE AND REGULATION
OF THE REPRODUCTIVE 'TRANSFEROME'.
Funded by the BBSRC, our
focus in this recent project is on a group of vitally important semen proteins
transferred along with sperm - the 'transferome'. It has been realized
for many decades seminal fluid proteins are far more than a simple sperm
buffer. In fact they can cause profoundly important effects on female
behaviour and physiology. These effects have been best studied in the
fruitfly but similar effects are also seen across a huge variety of
animal taxa including in humans.
In the fruitfly there are about
130 semen proteins making up the transferome. They result in a huge
variety of vitally important effects: they cause females to lay more
eggs, to eat more (and of different types of foods), to be less sexually
receptive to males, to switch on immune genes, to retain more sperm in
storage, to show altered patterns of water balance and to sleep less.
the importance of the transferome to both males and females and its
high degree of flexibility, we know little about how it is regulated. In
this project we investigate the control and regulation of this complex
and important system. We hypothesise that an effective way to regulate
130 individual components of the transferome is to manage them in 'sets'
controlled by regulatory hubs.
3. ALL'S FAIR WHEN LOVE IS WAR: THE EVOLUTION OF LIFESPAN AND AGEING UNDER SEXUAL CONFLICT.
has long been realised that the interactions between the sexes over
reproduction are often characterized by conflict rather than
co-operation. Hence the sexes often 'disagree' about how much energy and
resources to invest in reproduction and how often to make that
A good example is evolutionary disagreements over
how often to mate. Males often gain from mating frequently and females
often do not. Furthermore, females often suffer significantly reduced
lifespan from mating too frequently (an effect that is also seen in
These sexual interactions may underlie an important and
long-standing puzzle: why it is that males and females often have very
different longevity. For example, women generally live at least 4 years
longer than men.
The central aim of this research project, funded
by the NERC, is to (i) evaluate whether sexual conflict underlies
lifespan differences between males and females and (ii) identify the
underlying genes that are responsible.
4. COLONISATION, DOMESTICATION AND POPULATION CONTROL IN PEST INSECTS
world food supplies is a grand challenge. It is therefore of great
importance to develop safe, environmentally friendly and effective new
techniques for tackling pests of agriculturally important crops.
methods based on the release of mass reared insects have been applied
with some great successes. However, one potentially significant hurdle
remains. To release large numbers, pest insects are domesticated and
mass reared in laboratory facilities. This inevitably selects for
individuals that are highly successful in the laboratory, rather than in
the field. It is increasingly clear that a significant contribution to
health comes from associations with gut bacteria and changes to gut
bacteria are an important component of laboratory adaptation.
aim to understand how hosts and their gut bacteria adapt to laboratory
mass rearing conditions. With this knowledge, undesirable effects of
such adaptation can be slowed or reversed. The main objective, funded by
the BBSRC, is to use the medfly (an agricultural pest of world-wide
importance) to document changes in life history, gut bacteria, and their
interaction, upon colonization to the laboratory and the ability to
achieve population suppression.