An ovarian insulin-like peptide specifically regulates energy allocation and oocyte development in nutrition-restricted cockroaches

  • BMC Biol. 2025 Jul 28;23(1):226. doi: 10.1186/s12915-025-02342-4.
Yuan Luo  1 ,  Wen-Xin Hou  1 ,  Shan-Shan Zhao  1 ,  Yun-Long Cheng  1 ,  Ke-Jia Zhang  1 ,  Liang-Guan Lin  1 ,  Sheng Li  2 ,  Xiao-Jin Pei  3
Affiliations
  • 1. Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology and Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
  • 2. Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology and Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China. [email protected].
  • 3. Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology and Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China. [email protected].
PMID: 40717121 DOI: 10.1186/s12915-025-02342-4
Abstract

Background: Insects exhibit remarkable resilience and maintain high levels of reproduction despite frequently encountering nutritional restriction. However, the mechanisms governing their adaptive reproductive strategies under nutrition-restricted conditions remain poorly understood. The German cockroach Blattella germanica, a widespread urban pest, exhibits remarkable reproductive capabilities even in domestic environments where food resources are frequently limited.

Results: In this study, we demonstrate that the ovary plays a crucial role in promoting vitellogenin biosynthesis and oocyte development under nutrition-restricted conditions through hemiovariectomy. Employing transcriptome analysis, RNAi screening, and fluorescence in situ hybridization, we identified an ovarian-enriched insulin-like peptide gene (BgILP2) that is dramatically upregulated during low nutrition conditions. Repression of BgILP2 impairs vitellogenesis in the fat body through downregulation of p-AKT and p-ERK levels while simultaneously disrupting juvenile hormone synthesis, ultimately leading to delayed oocyte development under nutrient restriction. Furthermore, under low-nutrient conditions, repression of BgILP2 led to elevated circulating sugar levels, reduced lipid and glycogen storage, and a modest increase in the lifespan of female cockroaches.

Conclusions: The ovarian-enriched BgILP2 responds to nutritional stress and activates the Insulin signaling pathway to sustain oocyte development under nutrient-restricted conditions. Furthermore, BgILP2 mediates energy allocation and prioritizes reproductive investment potentially at the expense of longevity, which reflects a tradeoff between reproduction and somatic maintenance under nutrient restriction. These findings provide novel insights into the molecular mechanisms and adaptive strategies that enable cockroaches to maintain reproductive success in food-limited environments.

Keywords
German cockroach; Insulin-like peptide; Juvenile hormone; Lifespan; Nutritional restriction; Vitellogenesis.
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