A matrix model describing host–parasitoid population dynamics: The case of Aphelinus certus and soybean aphid

Abstract

Integrating elements from life tables into population models within a matrix framework has been an underutilized method of describing host–parasitoid population dynamics. This type of modeling is useful in describing demographically-structured populations and in identifying points in the host developmental timeline susceptible to parasitic attack. We apply this approach to investigate the effect of parasitism by the Asian parasitoid Aphelinus certus on its host, the soybean aphid ( Aphis glycines ). We present a matrix population model with coupled equations that are analogous to a Nicholson–Bailey model. To parameterize the model, we conducted several bioassays outlining host and parasitoid life history and supplemented these studies with data obtained from the literature. Analysis of the model suggests that, at a parasitism rate of 0.21 d −1 , A . certus is capable of maintaining aphid densities below economically damaging levels in 31.0% of simulations. Several parameters—parasitoid lifespan, colonization timeline, host developmental stage, and mean daily temperature—were also shown to markedly influence the overall dynamics of the system. These results suggest that A . certus might provide a valuable service in agroecosystems by suppressing soybean aphid populations at relatively low levels of parasitism. Our results also support the use of A . certus within a dynamic action threshold framework in order to maximize the value of biological control in pest management programs.

Towards Predictions of Interaction Dynamics between Cereal Aphids and Their Natural Enemies: A Review

“…Surprisingly, predation and/or parasitism processes are not often investigated in the empirical corpus, but are often represented in models. Many models represent predation or parasitism dynamics as Type-II or Type-III functional responses [ 57 , 62 ]. Other works recognize the scarcity of available information on certain parameters, such as parasitoid attack rates on aphids, and use their models to explore those parameters’ influences on aphid dynamics by varying their value over realistic ranges [ 63 ].…”

Parasitoid‐mediated indirect interactions between unsuitable and suitable hosts generate apparent predation in microcosm and modeling studies

“…Thus, the role played by milkweed aphid in our study may be generalized to other systems in which hosts of milkweed aphid (milkweed plants in North America and oleander in Europe) grow adjacent to other plants with suitable aphid hosts. In North America, this aphid has been found on milkweed plants growing inside and outside soybean field (Martin & Burnside, 1980) and A. certus is a biological control agent of the soybean aphid in both the United States and Canada (Frewin et al, 2010;Hallett et al, 2014;Kaser & Heimpel, 2018;LeBlanc & Brodeur, 2018;Miksanek & Heimpel, 2019). The presence of milkweed aphid within and adjacent to soybean fields in North America may therefore interfere with biological control of soybean aphid by Aphelinus certus.…”

A model for colour preference behaviour of spring migrant aphids

“…Aphids also serve as model species for the investigation of fundamental ecological questions, e.g. in the areas of endosymbiosis [2], multitrophic interactions [3], population dynamics [4], or climate change biology [5]. Aphid life cycles are highly diverse, with some species alternating between different host plant species, and many alternating between periods of sexual and asexual reproduction [6].…”