Under real-world conditions, the German cockroach Blattella germanica is frequently exposed to sublethal insecticide concentrations, yet the long-term consequences for population dynamics remain poorly understood. Here, we investigated the intergenerational effects of sublethal chlorpyrifos exposure in this urban pest. Newly emerged adults were treated with LD10 or LD30, and fitness-related traits and molecular responses were evaluated in the F0 and F1 generations. Sublethal exposure reduced fecundity and longevity in the F0 generation. Parental exposure also induced intergenerational effects in the F1 generation, including prolonged development, reduced survival, altered reproductive timing, and a decreased net reproductive rate. Population projection analysis indicated that LD10 suppressed long-term population growth. Chlorpyrifos further induced dose-dependent and intergenerational changes in detoxification-related genes, particularly BgCYP6ER1 and BgCYP6J1. In addition, mtDNA copy number increased under LD30, whereas BgCytb transcription was downregulated in the F1 generation, suggesting mitochondrial dysregulation under sublethal stress. These findings demonstrate that sublethal chlorpyrifos exposure can induce intergenerational effects on fitness-related traits and molecular responses. and highlight potential implications for pesticide risk assessment and resistance management.
The specificity of the olfactory system in the brain is determined not only by the expression of odorant receptor genes but also by the specific neural circuit assembly within the antennal lobe (AL). To investigate the developmental role of abnormal chemosensory jump 6 (acj6) in the moth Helicoverpa armigera, we generated Haacj6 mutants using CRISPR/Cas9 and examined the detailed structure of the AL based on immunostaining and three-dimensional reconstruction. The results showed that the AL in male Haacj6 mutants was markedly enlarged. In both sexes, the AL of Haacj6 mutants contained approximately 100 glomeruli, compared with about 75 glomeruli in wild-type. Glomerular volumes were also more heterogeneous in the mutants: the largest glomeruli were expanded, whereas the smallest were reduced, although the mean glomerular volume remained unchanged. These results demonstrate that the Haacj6 gene plays a critical role in normal AL development and that AL enlargement in the mutants arises primarily from the presence of additional glomeruli. These additional glomeruli likely reflect defects in olfactory receptor neuron axon wiring to AL projection neurons, or glial mediated glomerular boundary formation. These findings indicate that acj6 is an essential regulator of AL architecture and provide crucial insights into the molecular mechanisms governing neural circuits assembly in insects.
Organisms must reallocate limited resources to meet changing physiological demands, yet the cues that trigger these shifts and the physiological programs that mediate them remain poorly understood. For example, in some winged animals, females cannot simultaneously invest in energetically expensive flight musculature and egg production, requiring physiological transitions between dispersal and reproductive phases of their life cycle (the flight-oogenesis trade-off). However, the mechanisms that allow individuals to transition between dispersal and reproductive states remain unclear. Here, we test whether mating acts as a key external cue that reprograms internal resource allocation from somatic maintenance to reproduction. Using the wing-dimorphic variable field cricket Gryllus lineaticeps, we show that mating initiates flight muscle histolysis in long-winged females, eliminating any delay in early-life fecundity. Mating activates transcriptional programs associated with autophagy, iron mobilization, and endocrine signaling, consistent with a coordinated physiological shift that redirects nutrients from flight tissues to oogenesis. These mating-induced changes include altered insulin-like peptide and juvenile hormone signaling, suggesting that conserved hormonal pathways may be repurposed to govern life-history transitions. Together, our findings reveal that mating can serve as a potent trigger for reorganizing nutrient use and physiological priorities, enabling organisms to minimize the reproductive costs of non-reproductive states. By identifying a socially derived cue that initiates state transitions, this work provides a mechanistic framework for understanding how reproductive behaviors drive life-history strategies, and challenges long-standing assumptions about the inherent costs of dispersal.
Recent increases in the frequency and intensity of thermal anomalies can result in recurrent stressful weather events. Among annual insects, this phenomenon may expose parents and offspring to a succession of different weather anomalies (e.g. summer heatwaves and late spring frosts). Parental stress can alter offspring physiology and performance, potentially affecting their tolerance of environmental variation. We investigated the transgenerational effects of thermal anomalies on a univoltine wetland butterfly. We induced parental thermal stress by exposing pupae to a constant temperature, ranging from stressfully cold to stressfully hot (10 °C, 26 °C, 28 °C, 32 °C), for three days. Offspring were then subjected to either winter heatwaves or spring thermal anomalies. In the parental generation, pupal exposure to heat stress (32 °C) reduced adult longevity by 46%, while exposure to 28 °C maximized female reproductive output. Parental exposure to thermal stress did not affect offspring larval mass at the onset of diapause, but it did reduce offspring survival during winter and spring. Under winter heatwaves, survival was significantly higher among offspring of parents exposed to 26 °C than those exposed to 10 °C. Parental thermal stress was associated with decreased offspring survivorship in spring under control conditions and after a late frost. We observed anticipatory parental effects, as offspring of heat-stressed parents had increased survival under winter heatwaves, and negative transgenerational effects, as offspring of both heat and cold-stressed parents exhibited lower spring survivorship. We demonstrate a mechanism by which altered weather patterns can result in butterfly declines, highlighting the challenges that warming temperatures pose for insects.
Recent increases in the frequency and intensity of thermal anomalies can result in recurrent stressful weather events. Among annual insects, this phenomenon may expose parents and offspring to a succession of different weather anomalies (e.g. summer heatwaves and late spring frosts). Parental stress can alter offspring physiology and performance, potentially affecting their tolerance of environmental variation. We investigated the transgenerational effects of thermal anomalies on a univoltine wetland butterfly. We induced parental thermal stress by exposing pupae to a constant temperature, ranging from stressfully cold to stressfully hot (10 °C, 26 °C, 28 °C, 32 °C), for three days. Offspring were then subjected to either winter heatwaves or spring thermal anomalies. In the parental generation, pupal exposure to heat stress (32 °C) reduced adult longevity by 46%, while exposure to 28 °C maximized female reproductive output. Parental exposure to thermal stress did not affect offspring larval mass at the onset of diapause, but it did reduce offspring survival during winter and spring. Under winter heatwaves, survival was significantly higher among offspring of parents exposed to 26 °C than those exposed to 10 °C. Parental thermal stress was associated with decreased offspring survivorship in spring under control conditions and after a late frost. We observed anticipatory parental effects, as offspring of heat-stressed parents had increased survival under winter heatwaves, and negative transgenerational effects, as offspring of both heat and cold-stressed parents exhibited lower spring survivorship. We demonstrate a mechanism by which altered weather patterns can result in butterfly declines, highlighting the challenges that warming temperatures pose for insects.
