Book contents
- Frontmatter
- Contents
- Preface
- Part I Brief descriptive ecology: what do fleas do?
- Part II Functional ecology: how do fleas do what they do?
- 7 Ecology of sexual dimorphism, gender differences and sex ratio
- 8 Ecology of flea locomotion
- 9 Ecology of host selection
- 10 Ecology of haematophagy
- 11 Ecology of reproduction and pre-imaginal development
- 12 Ecology of flea virulence
- 13 Ecology of host defence
- Part III Evolutionary ecology: why do fleas do what they do?
- References
- Index
7 - Ecology of sexual dimorphism, gender differences and sex ratio
Published online by Cambridge University Press: 14 August 2009
- Frontmatter
- Contents
- Preface
- Part I Brief descriptive ecology: what do fleas do?
- Part II Functional ecology: how do fleas do what they do?
- 7 Ecology of sexual dimorphism, gender differences and sex ratio
- 8 Ecology of flea locomotion
- 9 Ecology of host selection
- 10 Ecology of haematophagy
- 11 Ecology of reproduction and pre-imaginal development
- 12 Ecology of flea virulence
- 13 Ecology of host defence
- Part III Evolutionary ecology: why do fleas do what they do?
- References
- Index
Summary
Males and females play complementary yet distinctly different evolutionary roles. They may differ in size and/or shape, behaviour and response to environmental factors. As a result, the abundance of males and females in a population may be unequal. This inequality in numbers may have important ecological and evolutionary consequences. This chapter starts with the description of differences in size, behaviour and physiology between male and female fleas. I attempt to understand how these differences are reflected in flea ecology. Then the effect of various gender differences on sex ratio in flea populations is considered.
Sexual dimorphism
Size dimorphism and Rensch's rule
Similar to many arthropods, fleas demonstrate strong female-biased sexual size dimorphism. This is true not only for species with neosomic females that are tens and hundreds of times larger than males (see Chapter 5) but also for species where gender size differences are less pronounced. For example, in six of seven flea species from the Negev Desert studied by Krasnov et al. (2003a), females were significantly larger than males (Fig. 7.1a).
Despite sexual size dimorphism occurring in a great number of animal species, male and female sizes usually covary within a lineage. However, in many cases variation in size is greater in males than in females (e.g. Fairbairn, 1997, 2005; Colwell, 2000). This generates an allometric pattern of sexual size dimorphism known as Rensch's rule.
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- Information
- Functional and Evolutionary Ecology of FleasA Model for Ecological Parasitology, pp. 79 - 102Publisher: Cambridge University PressPrint publication year: 2008