# Suppression of transgenerational lipid provisioning inhibits desiccation resistance, but not diapause, in the vector mosquito, Aedes albopictus

## TL;DR

The study shows that reducing lipid storage in mosquito mothers affects offspring survival during harsh conditions but does not impact diapause regulation.

## Contribution

The study reveals that transgenerational lipid provisioning influences overwinter survival traits but not diapause regulation in mosquitoes.

## Key findings

- Reducing lsd2 transcript levels in mosquitoes lowers egg triglycerides and increases desiccation and starvation vulnerability.
- Knockdown of lsd2 does not affect diapause incidence or its termination timing.
- Transgenerational lipid provisioning impacts overwintering fitness but not diapause regulation.

## Abstract

Transgenerational signaling allows many organisms to anticipate seasonal variation. Diapause, a hormonally-programmed period of developmental arrest, is a widespread anticipatory seasonal response that is often mediated by transgenerational signaling. Despite the well-established adaptive significance of diapause, the molecular and physiological basis of transgenerational diapause signaling remains largely unresolved. Since lipid accumulation is a hallmark of diapause preparation, we hypothesized that increased lipid provisioning and accumulation mediate transgenerational diapause signaling. To test this hypothesis, we suppressed transcripts of two lipid metabolism genes using RNA-interference in the maternal generation of the vector mosquito, Aedes albopictus. We show that a reduction in maternal lipid storage droplet 2 (lsd2) transcript abundance, but not diacyl-glycerol O-acyltransferase 1 (dgat1) transcript abundance, reduces egg triglyceride levels. Suppression of lsd2 in adult females also leads to increased egg desiccation, inhibits the starvation tolerance of larvae, and decreases egg overwinter survival. However, knockdown of lsd2 does not affect diapause incidence, the timing of diapause termination, and post-diapause development. Together, our results indicate that transgenerational lipid provisioning affects diapause-associated overwintering fitness traits, but not the regulation of entry into diapause or termination of diapause.