Influence of mating disruption treatments on male and female plodia interpunctella behavior

Authors: Campbell, James - Jim; Gerken, Alison; DRYER, DANIELLE

Submitted to: Proceedings, IOBC
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Mating disruption (MD) is a pest management tactic based on the release of large amounts of synthetic pheromone into the environment in order to disrupt mate-finding behavior. Mating disruption has a long research history as a pest management tactic for a range of insect species and crop systems. In stored product systems, MD products are available based on the active ingredient (9Z,12E)-9,12-tetradecadien-1-yl acetate (ZETA), which is a pheromone component shared by some important stored product moths: Indian meal moth, Plodia interpunctella (Hübner), tobacco moth, Ephestia elutella (Hübner), raisin moth, Cadra figulilella (Gregson), almond moth, Cadra cautella (Walker), and Mediterranean flour moth, Ephestia kuehniella (Zeller). While MD has been demonstrated to reduce moth abundance in field trials, reduction in numbers is often gradual under MD and while numbers can become quite low, complete suppression is not achieved. Incomplete suppression could result from processes like incomplete disruption of mating or the immigration of mated individuals into the space. Little information is available on the specific behavioral responses of males and females to ZETA MD treatments or the levels of spatial variation in efficacy under field conditions. Here we present a novel experimental approach to evaluate spatial variation in MD effects using P. interpunctella as a model. We used a long room (21.5 m length, 3.7 m width, 6.9 (average) height) in which a transect of observation locations was established (0, 3, 6, 9, 15, 18, and 21 m from a MD dispenser). The CideTrak IMM MD system (Trécé, Adair OK) was used in these studies, with dispenser number used based on the high or intermediate label rate and placed at the 0 distance on the transect. Control replicates did not have any MD dispensers. Two experimental approaches were initially used to address the questions about how distance from a dispenser influences behavior. In the first experimental approach, unmated male and female P. interpunctella were released at the mid-point of the transect and the number of eggs laid in food patches placed at different points along the transect were measured. This approach enabled the effects of the treatments on mating success (ability of males to find females) and the spatial pattern of oviposition (influence of MD on female behavior) to be determined. In the second experimental approach, the behavior of male and female moths was observed in small observation chambers placed at each point along the transect. Assays were recorded in the morning and in the evening. Moths in the chambers were recorded for 5 min with a barrier separating unmated males and females to determine how pheromone was affecting behavior of both sexes under potentially different pheromone concentration conditions. Moth behavior was then recorded for up to 5 min without the barrier to determine how courtship behavior is affected by potentially different background pheromone levels. Observations were terminated if copulation occurred. We were specifically interested in changes in mobility, calling behavior, courtship, and mating success as a function of MD treatment, distance, and time of day. The results and implications of these experiments will be summarized and discussed. There are a myriad of factors that influence MD treatment effectiveness in a food facility, and it can be challenging to determine their relative importance. Our experimental approach provides a system to evaluate different impacts of MD under relatively controlled conditions that also simulate more real-world environments and spatial scales. The information generated can be used to refine MD application methods in ways that improve overall efficacy.