An evaluation of two biochemical methods of age determination in insects (pteridines and lipofuscins) using the ant Polyrhachis sexpinosa Latrielle (Hymenoptera: Formicidae)

Abstract

Accurate information on the age of wild-caught animals is valuable for a variety of areas, but can be particularly difficult to obtain for small holometabolous insects, whose body size is fixed at the time of pupal eclosion. A variety of chemical groups, such as lipofuscins and pteridines accumulate in body tissues through time and can be used to predict age in a variety of arthropod taxa. Here we use spectrofluorometry to confirm the presence of extractable levels of lipofuscins and pteridines in individual social insects (using the ant Polyrhachis sexpinosa Latrielle, average body size 25 mg, as an example) and evaluate their ability to predict age. Pteridine levels were independent of age but lipofuscin levels increased with age in a predictable manner (r 2 = 72.8%). Lipofuscin levels therefore represent a new method of age determination for social insects that should be applicable to both individual laboratory and wild-caught animals.

Characterisation of variables associated with the flight behaviour of the rust-red flour beetle (Tribolium castaneum)

“…Lipofuscin intensities reveal that the molecule is not related to the age of beetles, which is contrary to what has been reported in the literature for other organisms, including ants, flesh flies and blue crabs (Ettershank et al, 1983;Ju et al, 1999;Robson & Crozier, 2009). Flying individuals of T. castaneum had higher lipofuscin intensities as compared to resident beetles.…”

“…Lipofuscin levels have been shown to increase with progressing age in many insects (Ettershank, 1983;Robson & Crozier, 2009;Terman et al, 2010). However, lipofuscin accumulation may also differ with different activities of an insect for example, flying houseflies had higher lipofuscin content as compared to low activity houseflies (Sohal & Donato, 1979).…”

“…The greatest intensity of the spectra (which corresponds to a λ emission = 410 nm) was recorded in arbitrary units. Spectral intensity at this wavelength is proportional to the lipofuscin concentration (Ettershank et al, 1983;Robson & Crozier, 2009). …”

“…The possibility of using lipofuscin as a marker of age was included because some studies have shown lipofuscin levels to be directly correlated with chronological age in ants, flesh flies and other organisms (Ettershank et al, 1983;Robson & Crozier, 2009). …”

Problems associated with a lipofuscin extraction method used to age blue crabs Callinectes sapidus cultured in Florida, USA

“…In arthropods, pteridine compounds ac cumulate over time and are also identified by similar fluorescence wavelengths (Sheehy 2008). Robson & Crozier (2009) compared the accumulation of pteridines and lipofuscin in the social ant Polyrhachis sexpinosa. Pteridine and lipofuscin extracts were excited at 355 and 340 nm and produced emissions at 445 and 410 nm, respectively.…”