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Abstract Parents can provide care to their offspring to increase their offspring's chance of survival. There are various types of parental care across insect taxa, one of which is maternal investment. Lipids, the most energy‐dense of macronutrients, are considered a good estimate of maternal investment in insects. However, it is not clear how different environments, such as host plants, can impact provisioning, especially for dietary generalists that feed on an array of plant species with varying quality. Using an extreme dietary generalist, fall webworm (FW,Hyphantria cunea), we investigated if females provision different amounts of lipids into their eggs depending on the diet they fed upon as larvae. We measured the lipid content of FW egg clusters from parents reared on seven host plant species of varying quality. We found that parental host plants influenced egg provisioning, such that provisioning depends on host plant but also increases most for parents reared on low‐quality diets. Additionally, we found that female parents with heavier pupal mass produced egg clusters with greater lipids per egg. Our results provide evidence that egg provisioning can depend on the parental environment and suggest that the use of low‐quality host plants by generalist herbivores may be partially overcome via maternal investment.
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Variation in immune response in the generalist herbivore fall webworm across four common host plants
Abstract Dietary generalist herbivorous insects are widespread and often occur in a variety of environments. Across their geographic range, herbivorous insects may encounter variable plant traits as they feed on high‐quality or low‐quality plants. Herbivorous insect larvae experience both bottom‐up (host plant) and top‐down (parasitoid) factors that affect survival. Host plant quality may affect larval growth and survival in that larvae feeding on low‐quality plants often suffer reduced fitness. However, herbivores on different host plants are also subject to different levels of parasitism. High‐quality plants confer stronger larval performance (higher survival, more offspring), but larvae may also face higher parasitism. In some herbivore species, diet mediates larval immune response. The generalist insect herbivore fall webworm (FW),Hyphantria cuneaDrury (Lepidoptera: Erebidae), is a moth native to North America, and its larvae have considerable variance in their performance when reared on different host plants. We investigated whether diet affects the immune response in FW larvae when they are reared on different host plant species known to vary in food quality. We measured immune response by melanization of a nylon filament. We found significant differences in immune response across host plants, indicating that diet mediates immune response in FW larvae. Our study helps elucidate the factors that cause variation in immune response in a generalist herbivore.
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- PAR ID:
- 10630393
- Publisher / Repository:
- Entomologia Experimentalis et Applicata
- Date Published:
- Journal Name:
- Entomologia Experimentalis et Applicata
- Volume:
- 172
- Issue:
- 11
- ISSN:
- 0013-8703
- Page Range / eLocation ID:
- 1008 to 1013
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Why and how herbivorous insects choose to feed on some plant species and not others can be influenced by many factors; however, it is not always clear why herbivorous insects will choose to lay their eggs on some plants over others. The Hopkins’ host selection principle (hereafter HHSP) hypothesizes that female insects prefer to lay eggs on host plants upon which they fed as larvae, but there are studies that both support and refute the hypothesis. Here, we test HHSP in a dietary generalist moth, fall webworm (Hyphantria cunea, hereafter FW). Previously, local host plant abundance has been the only factor found to determine FW host plant use; whether FW exhibit individual host plant preferences is unknown. We conducted preference tests with females of the two FW morphotypes (red-head and black-head), presenting females with four host plants: their one natal host plant, two other potential host plants, and one non-host plant for that morphotype that is a host plant for the other morphotype. Overwhelmingly, females of both morphotypes oviposited on a non-plant surface in the choice arena and those that did oviposit on a plant did not distinguish between host plants and non-host plants. Of the few FW females that oviposited on a host plant, only red-head females showed preference for their natal hosts. Our results support previous findings that HHSP is not a strong driver of host plant selection, suggesting that female FW are not selective in their choice of host plants, which may facilitate generalism in this species.more » « less
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/eea.13502
