Influence of phosphine resistance genes on flight propensity and resource location inTribolium castaneum(Herbst) (Coleoptera: Tenebrionidae): the landscape for selection

Abstract

Phosphine resistance in Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) has evolved through changes to enzymes involved in basic metabolic pathways. These changes impose metabolic stress and could affect energy‐demanding behaviours. We therefore tested whether phosphine resistance alleles impact the movement of these insects in their quest for new resources. We measured walking and flight parameters of four T. castaneum genotypes: (1) a field‐derived population, (2) a laboratory cultured, phosphine‐susceptible reference strain, (3) a laboratory cultured, phosphine‐resistant reference strain, and (4) a resistant introgressed strain that is almost identical genetically to the susceptible population. The temporal pattern of flight was identical across all populations, but resistant beetles took flight significantly less, walked more slowly, and located resources less successfully than did susceptible beetles. Also, the field‐derived beetles (proved not to be carrying resistance genes) walked significantly faster and more directly towards food resources, and had a higher propensity for flight when compared to the susceptible laboratory beetles. These negative effects suggest survival of beetles with the resistance alleles will be compromised should they leave phosphine application sites. The field for selection therefore extends beyond the site at which phosphine fumigant imposed its effect, and other mutations are also likely to be affected in this way.

Phosphine fumigation and the ecology of the rust red flour beetle, Tribolium castaneum: the effects of phosphine resistance genes and sublethal exposure

“…castaneum and suggested their flight activity is a mechanism to disperse, but is not related to the proposed oogenesis-flight syndrome of migratory insects (Johnson 1963). Females showed the greatest propensity to take flight (on average about 1.3 times than males) ( Similar to the result of previous work, significantly more susceptible beetles initiated flight compared with beetles known to carry phosphine resistant alleles (Malekpour et al, 2016).…”

“…In some studies, emigration rates correlated with density (Fadamiro et al, 1996), but in many more they do not (Perez-Mendoza et al, 2011). This investigation therefore focuses on a system in which a genetic influence on propensity to fly has been demonstrated recently, and in which the same genes influence the ability of the insects to localize suitable resources (Malekpour et al, 2016), as explained next.…”

“…Some factors involved in T. castaneum taking flight have been examined, for example, temperature (Cox et al, 2007), population density (Perez-Mendoza et al 2011a, b) and aspects of the physiological state of the insects (Fedina andLewis 2007, Perez-Mendoza et al, 2011a, b), Also, the influence of wind direction in the field on the orientation of their flight, which is largely downwind, has been quantified, and it is clear they do not fly when wind speed is too high (> ~ 3 m/s) (Rafter et al, 2015). The role of genes in emigration of the beetles by flight, and the colonization of new resources remains unclear, but the previous study showed that genes associated with resistance to phosphine are associated with a reduced propensity to fly, as well as a decrease in velocity and more turning whilst walking towards a food resource (Malekpour et al, 2016). These features have consequences for the behaviour associated with beetles leaving an environment that is still of good quality for them, and the subsequent colonization of new resources.…”

“…Daily assessments were run between 1000h and 1500h with different food resources and beetles of different sexes and strains. They were tested at this time because their tendency to fly is low during this period (Malekpour et al, 2016). Walking velocity (cm/s) was calculated with EthoVision tracking software.…”

“…In particular, the lower movement ability both by walking and flight of the phosphine-resistant reference beetles (Malekpour et al, 2016) leads to the undertaking migratory flight at a relatively lower frequency than susceptible reference beetles and being less efficient (with respect to time) in locating to the resources in the field. Although the food resource that was not most attractive to phosphine resistant reference beetles was the same as for susceptible reference ones, the resistant reference beetles took much longer time (1.6 times) to find the food than did the susceptible reference ones, which is attributable to the pleiotropic effect of the phosphine resistant genes on the movement abilities of these insects.…”