Triacylglycerides and egg-to-adult viability in Drosophila melanogaster

Triacylglycerides (TAGs) are neutral lipids and are one of the major
energy storage form in an insect aiding in normal physiology including
reproduction of the organism. Importance of TAG metabolism in
gametogenesis has been investigated in insects like mosquitoes, silkworm
and Drosophila. However, a direct association between TAG levels and
egg-to-adult viability has not been explored. In this study, we have
assessed levels both stored and circulating TAG levels and egg-to-adult
viability in Drosophila melanogaster lines with varying genetic
backgrounds established through inbreeding and recombinant inbreeding
strategies. We found noticeable variation in egg-to-adult viability and in
both stored and circulating TAG levels in D. melanogaster lines.
Apparently the D. melanogaster lines with higher levels of circulating TAG
also had a higher egg-to-adult viability. To validate this, analysis of
these variations through supervised correlation and unsupervised K-means
clustering showed that levels of circulating TAG are positively associated
with egg-to-adult viability irrespective of gender. The findings suggest
that levels of circulating TAG promotes successful transition of egg to an
adult. Taken together, the findings not only have a potential application
in husbandry of ecologically and economically important insects but holds
importance in translational research in fertility of vertebrates including
humans.