There are 3559 species of mosquitoes in the world (Harbach 2018) but, so far, only a handful of them have been a focus of olfactory neuroscience and neurobiology research. Here we discuss mosquito olfactory anatomy and function and connect these to mosquito ecology. We highlight the least well-known and thus most interesting aspects of mosquito olfactory systems and discuss promising future directions. We hope this review will encourage the insect neuroscience community to work more broadly across mosquito species instead of focusing narrowly on the main disease vectors.

Animals can make use of camouflage to reduce the likelihood of visual detection or recognition and thus improve their chances of survival. Background matching, where body colouration is closely matched to the surrounding substrate, is one form of camouflage. Hermit crabs have the opportunity to choose their camouflage independently of body colouration as they inhabit empty gastropod shells, making them ideal to study their choice of camouflage. We used 3D-printed artificial shells of varying contrasts against a grey substrate to test whether hermit crabs prefer shells that they perceive as less conspicuous. Contrast-minimising shells were chosen for Weber contrasts stronger than -0.5. However, in looming experiments, animals responded to contrasts as weak as -0.2, indicating that while they can detect differences between shells and the background, they are only motivated to move into those shells when the alternatives contrast strongly. This suggests a trade-off between camouflage and vulnerability introduced by switching shells.

Animal warning signals show remarkable diversity, yet subjectively appear to share visual features that make defended prey stand out and look different from more cryptic palatable species. Here we develop and apply a computational model that emulates avian visual processing of pattern and colour to Lepidopteran wing patterns to show that warning signals have specific neural signatures that set them apart not only from the patterns of undefended species but also from natural scenes. For the first time, we offer an objective and quantitative neural-level definition of warning signals based on how the pattern generates neural activity in the brain of the receiver. This opens new perspectives for understanding and testing how warning signals function and evolve, and, more generally, how sensory systems constrain general principles for signal design.