Plasticity and modulation of olfactory circuits in insects

Abstract

Olfactory circuits change structurally and physiologically during development and adult life. This allows insects to respond to olfactory cues in an appropriate and adaptive way according to their physiological and behavioral state, and to adapt to their specific abiotic and biotic natural environment. We highlight here findings on olfactory plasticity and modulation in various model and non-model insects with an emphasis on moths and social Hymenoptera. Different categories of plasticity occur in the olfactory systems of insects. One type relates to the reproductive or feeding state, as well as to adult age. Another type of plasticity is context-dependent and includes influences of the immediate sensory and abiotic environment, but also environmental conditions during postembryonic development, periods of adult behavioral maturation, and short- and long-term sensory experience. Finally, plasticity in olfactory circuits is linked to associative learning and memory formation. The vast majority of the available literature summarized here deals with plasticity in primary and secondary olfactory brain centers, but also peripheral modulation is treated. The described molecular, physiological, and structural neuronal changes occur under the influence of neuromodulators such as biogenic amines, neuropeptides, and hormones, but the mechanisms through which they act are only beginning to be analyzed.

Mating behaviour, mate choice and female resistance in the bean flower thrips (Megalurothrips sjostedti)

“…Older males have less long to live on average and might therefore be expected to become less choosy and less likely to miss a mating opportunity rather than more. The effect may be the result of age-dependent increases in olfactory sensitivity 49 . The degree of male choosiness might also be influenced by the number of females arriving at an aggregation.…”

Latest Developments in Insect Sex Pheromone Research and Its Application in Agricultural Pest Management

“…These findings show that, in nature, sex pheromone and plant odors are perceived as an ensemble, and mating and habitat cues are coded as blends in the MGC of the AL highlighting the dual role of plant signals in habitat selection and in premating sexual communication [ 120 ]. Very recently, reviews on the plasticity and modulation of olfactory circuits of insects in a complex environment with different odorants and pheromones, and new neuroecological studies directed to understand the evolution of insect sensory systems, have been published [ 124 , 125 ]. These studies could eventually provide us with potential tools to protect endangered species and reduce the risk for the invasion of alien species.…”

Insects Provide Unique Systems to Investigate How Early-Life Experience Alters the Brain and Behavior

“…The developmental environment, including simple abiotic factors like temperature and moisture, impacts a variety of sophisticated behaviors from dispersal patterns (Zera and Denno, 1997;Alyokhin and Ferro, 1999;Benard and McCauley, 2008) to social and reproductive tactics (Radwan, 1995;Emlen, 1997;Taborsky and Brockmann, 2010;Łukasik, 2010;Kasumovic and Brooks, 2011). Thus, in controlled but environmentally relevant experiments, it is possible to assess how specific types of developmental inputs shape both sensory and integrative processes (Anton and Rossler, 2020;Fernandez et al, 2020;Gonzalez-Tokman et al, 2020) relevant to many different behavioral phenotypes. In addition, the short generation time of insects is ideal for life-long studies of behavior.…”