Life history changes in Trogoderma variabile and T. inclusum due to mating delay with implications for mating disruption as a management tactic

Abstract

Controlling postharvest pest species is a costly process with insecticide resistance and species‐specific control requiring multiple tactics. Mating disruption (MD) can be used to both decrease a female's access to males and delay timing of mating and decreases overall mating success in a population and population growth rate. Development of new commercially available MD products requires an understanding of life history parameters associated with mating delay. These can provide information for targeting proportions of reproducing individuals using MD. After delaying mating for females of two closely related beetle species, Trogoderma variabile and T. inclusum, we surveyed survivorship, number of eggs laid, and number of progeny emerged. With increases in mating age, total number of eggs laid and total number of progeny emerged significantly declined over time. T. inclusum typically had greater numbers of eggs laid and progeny emerged compared to T. variabile as female age at mating increased, suggesting that T. inclusum may be more resistant to long‐term delays in mating. Life span showed an increase as mating age increased but life span significantly decreased almost immediately following mating. Simulations depicting multiple distributions of mating within a population suggest that in a closed population, high levels of mating delay significantly reduced reproductive growth rates. Although reproductive growth rates were decreased with increased mating age, they are still large enough to maintain populations. This study highlights the differences in life history between two closely related species, suggesting that T. inclusum outperforms T. variabile over the course of a life span, but T. variabile has better reproductive capabilities early in life. MD may also be a viable component of a pest management system for these two species as it significantly decreased overall reproductive output and population growth.

Ecology of female mating failure/lifelong virginity: a review of causal mechanisms in insects and arachnids

“…In some cases, physiological age (days before death) has a stronger influence on mating decisions than chronological age (days since emergence) (Ligout et al, 2012). In short-lived insects, delayed mating reduces lifetime fecundity of females due to metabolic cost of survival during the latency period combined with reduced duration of post mating oviposition period (Mori & Evenden, 2013;Gerken & Campbell, 2018). In purely monandrous species, mated females do not seek additional copulations unless they copulated with a poor-quality male (Elzinga et al, 2011;Forbes, 2014).…”

Automated Applications of Acoustics for Stored Product Insect Detection, Monitoring, and Management

“…Finally, we note the increased usage of acoustic detection methods against invasive stored product pests, e.g., Trogoderma inclusum LeConte [ 276 ] and other invasive Trogoderma spp. [ 15 , 277 ].…”

Towards developing areawide semiochemical‐mediated, behaviorally‐based integrated pest management programs for stored product insects

“…It is interesting to note that four of the five species for which there are mating disruption tools are moths. Mating disruption may primarily target moths because adults are short‐lived, whereas many stored product beetles are long‐lived, presenting more opportunities for finding mates and thwarting mating disruption technology 65,66 . In addition to the biological limitations, there may be some regulatory considerations that have resulted in mating disruption only being available for pyralid moths in stored products.…”

“…anhydroserricornin) may also be attractive, 68 but recent research has called this into question when assessing the compound's ability to attract conspecifics to traps 69 . There has also been interest in developing mating disruption for Trogoderma spp., 65 but there has not yet been any successful implementation. This may provide further impetus for why additional kinds of behaviorally‐based tactics should be developed.…”