Biology subjects

Peirce, M. J.

Publications and source records attributed to Peirce, M. J..

5 recordsLinked to original sources

bioRxiv2025

Experimental evidence of male-male interaction in laboratory swarms of Anopheles gambiae mosquitoes

Mosquitoes mostly mate in the context of swarms: to facilitate encounters with females, males form disordered aggregations over a visual marker, which serves as a positional reference. Due to the scarcity of high-resolution data, it remains unclear whether swarms are the result of individuals interacting independently with the marker, or whether they are the expression of a genuine collective behavior produced by spontaneous interaction between individuals. Here, with a unique dataset comprising three-dimensional trajectories of 30 laboratory swarms of different size (ranging from 80 to 400 mosquitoes), we investigate swarming behavior of Anopheles gambiae mosquitoes. With a statistical physics approach, we provide experimental evidence of an effective male-male interaction. We find that individual speed fluctuations are strongly correlated in space, meaning that mosquitoes in close proximity tend to display similar deviations from the group average, effectively flying at a similar speed. We prove that this correlation is not compatible with a random arrangement of individuals, indicating that an interaction process is at play.

animal behavior and cognition↗

bioRxiv2025

JNK signaling regulates reproductive trade-offs after Plasmodium infection in the malaria mosquito

Environmental stress can limit mammalian reproduction by affecting production of sexual steroid hormones. Here we reveal a similar mechanism in the malarial mosquito Anopheles gambiae: activation of the stress-sensitive c-Jun N-terminal kinase, JNK, constrains reproductive investment by suppressing production of ecdysteroids that orchestrate egg development in this species. We show that infection with Plasmodium berghei parasites increases JNK signalling in the reproductive tract causing a JNK-dependent reduction in both egg development and mosquito survival. Moreover, JNK signaling supresses expression of Cyp315a1 (AGAP000284), a rate-limiting enzyme in ecdysteroid synthesis, a transcriptional change reflected in reduced ecdysteroid production following an infected blood meal. A similar mechanism limits egg production under other stressors (heat stress, or ectopic activation of JNK signaling). Together, these data reveal a regulatory circuit whereby Plasmodium infection curtails reproductive investment in an important vector of human malaria, one that may be applicable to environmental stressors more generally.

zoology↗

bioRxiv2025

Controlling malaria mosquito reproduction via the octopamine beta2 receptor

Mosquito reproduction in a broad sense involves multiple steps from acoustic recognition of mating partners to egg hatching. We show that the octopamine receptor AgOct{beta}2R controls different aspects of this process in a sexually dimorphic manner. AgOct{beta}2R knockout males present auditory defects that impair their ability to inseminate females, whilst knockout females are sterile. These phenotypes suggest AgOct{beta}2R as a target to impair mosquito reproduction at multiple levels. We test the reproductive effects of the insecticide amitraz, an AgOct{beta}2R agonist, showing that amitraz exposure reduces insemination in the lab but not in the field and has no effects on female sterility, excluding its applicability as a mating disruptor. Pharmacological assays reveal that AgOct{beta}2R sensitivity to amitraz is reduced compared to other arthropods, but its responses can be altered by modifying residues in the binding pocket. Together, our results establish AgOct{beta}2R as a promising target to disrupt mosquito reproduction but emphasize the necessity of developing new tools to exploit this approach.

neuroscience↗

bioRxiv2022

20E-dependent tyrosine phosphorylation of phospholipase C gamma underpins egg development in the malaria vector Anopheles gambiae

The efficient development of eggs following a blood meal is central to the vector capacity of Anopheles gambiae females. The ecdysteroid hormone 20-hydroxyecdysone (20E) plays a pivotal role in this process, yet the signaling mechanisms by which 20E exerts its effects remain incompletely understood. Here we show blood feeding is associated with increased tyrosine phosphorylation of an array of proteins coincident with the increase in titers of 20E that follows a blood meal. Injection of genistein, a tyrosine kinase inhibitor, reduces both the appearance of phosphotyrosine-containing proteins and fecundity, linking tyrosine phosphorylation to egg development. We identify one of the proteins phosphorylated after a blood meal as phospholipase C gamma (PLC{gamma}) and show that its blood feeding-induced phosphorylation is dependent on endogenously synthesized 20E via the ecdysone receptor (EcR). Interruption of Src-like tyrosine kinase signaling inhibits phosphorylation of PLC{gamma} as well as egg development after blood feeding, implicating Src-like kinases in the phosphorylation of PLC{gamma}. Taken together, these data suggest that the effects of 20E on An. gambiae egg development are at least partially mediated through a tyrosine phosphorylation-dependent signaling cascade involving Src family tyrosine kinases and PLC{gamma}.

biochemistry↗

bioRxiv2020

JNK signaling regulates oviposition in the malaria vector Anopheles gambiae

The reproductive fitness of the Anopheles gambiae mosquito represents a promising target to prevent malaria transmission. The ecdysteroid hormone 20-hydroxyecdysone (20E), transferred from male to female during copulation, is key to An. gambiae reproductive success as it licenses females to oviposit eggs developed after blood feeding. Here we show that 20E-triggered oviposition in these mosquitoes is regulated by the stress- and immune-responsive c-Jun N-terminal kinase (JNK). The heads of mated females exhibit a transcriptional signature reminiscent of a JNK-dependent wounding response while mating -- or injection of virgins with exogenous 20E -- selectively activates JNK in the same tissue. RNAi-mediated depletion of JNK pathway components inhibits oviposition in mated females, whereas JNK activation by silencing the JNK phosphatase puckered induces egg laying in virgins. Together, these data identify JNK as a potential conduit linking stress responses and reproductive success in the most important vector of malaria.

animal behavior and cognition↗