Candidate foraging gene orthologs in a lower termite, Reticulitermes flavipes

Abstract

Under a sociogenomic context, the molecular mechanisms underlying gene-behavior associations are of particular interest. The Drosophila foraging (for) gene has been demonstrated to have a causal role in insect behavioral plasticity. Previous studies of for have revealed many facets of for function, including roles in foraging, energy metabolism, learning and memory, circadian rhythm, and stress resistance. for orthologs have been identified in a variety of insect taxa. However, expression patterns are not consistent across all insects, with for orthologs serving as both positive and negative regulators of foraging behavior. In this study, we cloned two for orthologs, Rffor-α and Rffor-β, from the Eastern subterranean termite, Reticulitermes flavipes. Spatial distribution study showed that the termite brain possesses significantly higher expression levels of Rffor-α and Rffor-β than other types of tissues, which suggests that for may act on the brain to influence an individual's ability to respond to its environment. The temporal expression profile of Rffor across different developmental stages suggests that Rffor functions as a negative regulator of foraging behavior. However, results from environmental impacts, that is, temperature and photoperiod, do not fit under a model of negative correlation between gene expression and locomotion. Further testing is warranted to better understand the interaction between Rffor expression and the environment. K E Y W O R D S for gene, foraging behavior, PKG, Reticulitermes flavipes, termite

The cGMP‐dependent protein kinase gene can regulate trail‐following behaviour and locomotion in the termite Reticulitermes chinensis Snyder

“…We successfully identified and characterized the for ortholog gene of the termite R. chinensis ( PKG ). The results of our multiple amino acid sequence alignments indicated that the gene PKG shared the highest sequence identity with Rffor ‐ α , which is one of PKG type I isoforms, was found recently in the termite R. flavipes (Merchant et al, 2020). Type I PKGs had been reported to be associated with foraging in insects (Allen et al, 2017; Chardonnet et al, 2014; Kodaira et al, 2009; Lucas et al, 2010; Tobback et al, 2008), and Rffor‐α was more functionally associated with foraging than Rffor‐β (the another one of PKG type I isoforms) in R. flavipes (Merchant et al, 2020).…”

“…In addition, for orthologs have been identified in a variety of insects including honey bees (Ben‐Shahar et al, 2003), ants (Ingram et al, 2005; Lucas et al, 2015), locusts (Lucas et al, 2010) and some other insects (Chardonnet et al, 2014; Marliére et al, 2015; Tarès et al, 2013). A recent study showed that two for orthologs, Rffor‐α and Rffor‐β , were cloned from the termite Reticulitermes flavipes and found that Rffor may play a role in locomotor activity rather than being exclusively linked to foraging (Merchant et al, 2020). Nevertheless, further testing is necessary to verify the role of the for gene in regulating locomotion in termites.…”

Theforaginggene as a modulator of division of labour in social insects

“…The association between the PKG activity of the foraging gene and behavioural plasticity in response to changes in the social and biotic environments, especially in the context of feeding and foraging behaviours, is conserved across a broad range of animal species, from insects to humans (Anreiter & Sokolowski, 2019;Armstrong et al, 2010;Chardonnet et al, 2014;Kohlmeier et al, 2019;Lucas, Kornfein, et al, 2010;Malé et al, 2017;Merchant et al, 2019;Robertson & Sillar, 2009;Struk et al, 2019;Tarès et al, 2013;Tobback et al, 2013). Additionally, it remains unknown whether all or only some of the alternative transcripts transcribed by for in at least some social insect species play a role in regulating neuronal plasticity and behaviour in social insects (Lucas & Sokolowski, 2009;Merchant et al, 2019;NCBI, 2021). Furthermore, the specific molecular targets and neuronal signalling pathways modulated by for activity across the evolutionary, developmental, and physiological timescales remain a mystery.…”

“…For example, a study on the comparisons of brain gene expression between the social wasp Polistes metricus and the honey bee Apis mellifera allowed to identify common molecular roots for division of labour, demonstrating the importance of for across lineages (Amy L . In the termite Reticulitermes flavipes, a recent study showed differences in mRNA expression depending on caste, temperature and photoperiod (Merchant et al, 2019), suggesting the possibility that the differential expression of for may very well be important for this social insect group as well. Future comparisons between termites and social hymenopteran will likely shed even more light on how for regulates division of labour across phylogenetically distant social systems (Hymenoptera/Isoptera) with distinct developmental processes (e.g., holometabolism vs. hemimetabolism).…”

Abnormal energy metabolism can alter foraging behavior in termites in different social contexts

“…Theoretically, both inherent genes and external social contexts can influence foraging behavior in insects. The foraging gene (for), encoding a cGMP-dependent protein kinase (PKG), is related to the foraging behavior of several social and solitary insects, including the lower termite R. flavipes [33], the fruit fly Drosophila melanogaster [34,35], the honey bee Apis mellifera [36], the bumblebee Bombus ignites [37], the red harvester ant Pogonomyrmex barbatus [38], the ant Pheidole pallidula [39] and the fire ant Solenopsis invicta [40]. In solitary D. melanogaster,…”