Biology subjects

Iacomelli, G.

Publications and source records attributed to Iacomelli, G..

3 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↗