Data from: Exoskeleton ageing and its relation to longevity and fecundity in female Australian Leaf Insects (Phyllium monteithi)

Senescence is a decline in reproduction and survival rate with advancing
age resulting from deterioration of somatic tissues and systems throughout
the body. Age-related somatic changes (somatic ageing) have been studied
extensively in vertebrates but are less well known in other animals,
including insects. Since adult insects have very limited ability to repair
their exoskeleton, somatic ageing could involve deterioration and
discolouration of the cuticle. We investigated age-related changes in wing
pigmentation and abdominal cuticle necrosis in females of the Australian
leaf insect Phyllium monteithi. Adult females varied markedly in the
extent and pattern of pigmentation on their bodies, and we found that
pigment spots on the forewings increased in size with age in most
individuals. As females aged, most individuals also exhibited increasing
levels of abdominal cuticle necrosis, resulting in the loss of abdominal
cuticle along the margin of the abdomen. Neither the extent of
pigmentation nor cuticle loss were clearly associated with reduced
fecundity or longevity in the protected laboratory environment, but it
remains unknown whether these age-related changes have functional
implications in the wild. Our results show that the P. monteithi
exoskeleton undergoes complex changes with age, with potential
implications for functional traits and fitness.