Repeated Copulation and Guarding, and Their Relationship With Male and Female Morphological Traits in the Water Scorpion .

Insects copulate multiple times not only with different mates but also with the same mate, which is called repeated copulation. It occurs as a repeated alternation between copulation and mate-guarding, leading to the prolonged physical attachment between males and females. Particularly, in species where males forcefully grasp females, attempt to mate without courtship and exhibit repeated copulations, male and female morphological traits are expected to be associated with mating characteristics.

Age-Related Plasticity Integration in Male Cicadas : Are Adult Cicadas Capital Breeders?

Labile traits, such as behavioural, physiological traits or body mass, vary within an individual either over time or across environments. Such changes within an individual can be linked across traits, forming within-individual trait correlations. These correlations are particularly expected when ageing causes changes in the expression of multiple traits.

Activity-aggression behavioural syndromes exist in males but not in females of the field cricket .

Previous studies on sex differences in behaviour have largely focused on differences in average behaviours between sexes. However, males and females can diverge not only in average behaviours but also in the direction of behavioural correlations at the individual level (i.e.

Density-dependent sex-biased development of macroptery in a water strider.

In wing-polymorphic insects, wing morphs differ not only in dispersal capability but also in life history traits because of trade-offs between flight capability and reproduction. When the fitness benefits and costs of producing wings differ between males and females, sex-specific trade-offs can result in sex differences in the frequency of long-winged individuals. Furthermore, the social environment during development affects sex differences in wing development, but few empirical tests of this phenomenon have been performed to date.