The nutritional landscape of host plants for a specialist insect herbivore

Abstract

Nutrition has far‐reaching effects on both the ecology and evolution of species. A substantial body of work has examined the role of host plant quality on insect herbivores, with a particular focus on specialist–generalist dynamics, the interaction of growth and other physiological attributes on fitness and tritrophic effects. Measures of plant quality usually involve one or two axes of nutritional space: typically secondary metabolites or elemental proxies (N and C) of protein and carbohydrates, respectively.Here, we describe the nutrient space of seven host plants of the specialist insect herbivore, Manduca sexta, using an approach that measures physiologically relevant sources of nutrition, soluble protein and digestible carbohydrates. We show that plant species differ markedly in their nutrient content, offering developing insect herbivores a range of available nutrient spaces that also depend on the age of the leaves being consumed.The majority of host‐plant species produce diets that are suboptimal to the herbivore, likely resulting in varying levels of compensatory feeding for M. sexta to reach target levels of protein to ensure successful growth and development. Low‐quality diets can also impact immune function leading to complex patterns of optimization of plant resources that maximizes both growth and the ability to defend from parasitoids and pathogens. This study is the first to quantify the nutrient space of a suite of host plants used by an insect herbivore using physiologically relevant measures of nutrition.

Plant Nutrition Influences Resistant Maize Defense Responses to the Fall Armyworm (Spodoptera frugiperda)

“…The relationships between plants and insects in the context of resource partitioning and defenses is not unidirectional. Insects encounter heterogenous nutritional landscapes (Behmer, 2009), arising from species or genotypic traits associated with plant nutrient uptake ability or efficiency (Abbas et al, 2011;Wilson et al, 2019), as well as host-plant access to nutrients in the soil (Lavoie and Oberhauser, 2004;Prudic et al, 2005;Rashid et al, 2017). Insect performance metrics are commonly limited by the nutritional components of their diet (Awmack and Leather, 2002;Behmer, 2009), and nutrient variation can alter herbivore performance and population dynamics (Chen et al, 2010;Wetzel et al, 2016).…”

Effects and correlation analysis of different host-plant components on physiological indexes in Spodoptera frugiperda

“…There are different nutrient and secondary substance content with different hosts (Wilson et al, 2019).…”

Host quality does not matter to native or invasive cactus moth larvae: grave implications for North American prickly pears

“…Nevertheless, we argue that simple nutritional characterization of host plant quality was a useful exercise that can be explanatory of host plant usage in general, and specifically in this system. This is especially true for closely related herbivore species confronted with a suite of potential host plants species in the same genus (Deans et al ., 2015; Wilson et al ., 2019).…”

“…Most plant-insect interactions are characterised by herbivorous insects specializing on specific plant species (Forister et al, 2015). Specialist insects have narrow relationships with host plants for many reasons such as superior nutritional quality (Wilson et al, 2019), ability to overcome Correspondence: Colin R. Morrison, Department of Integrative Biology, The University of Texas at Austin, Graduate Program in Ecology Evolution and Behavior, 2415 Speedway, Austin, TX, 78712, U.S.A. E-mail: crmorrison@utexas.edu complex suites of secondary metabolites (Becerra et al, 2009;Glassmire et al, 2016), behaviour suited for particular hosts (Strong, 1977;Damman, 1987), enhanced ability to locate hosts (Berenbaum, 1990;Thiele et al, 2016), or ability to use hosts as enemy-free-space (Price et al, 1980). Many historical and proximate factors produce a mosaic of interactions between specialist insects and their host plants, and this heterogeneity affects emergent properties from populations to ecosystems (Thompson, 2005).…”