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Functional food webs are essential for the successful conservation of ecological communities, and in terrestrial systems, food webs are built on a foundation of coevolved interactions between plants and their consumers. Here, we collate published data on host plant ranges and associated host plant-Lepidoptera interactions from across the contiguous United States and demonstrate that among ecosystems, distributions of plant-herbivore interactions are consistently skewed, with a small percentage of plant genera supporting the majority of Lepidoptera. Plant identities critical for retaining interaction diversity are similar and independent of geography. Given the importance of Lepidoptera to food webs and ecosystem function, efficient and effective restoration of degraded landscapes depends on the inclusion of such 'keystone' plants. Not all plants are equally able to support native insects. Here, the authors use data on interactions among >12,000 Lepidoptera species and >2000 plant genera across the United States, showing that few plant genera host the majority of Lepidoptera species; this information is used to suggest priorities for plant restoration. [ABSTRACT FROM AUTHOR]

This study compares caterpillar communities (Lepidoptera and Hymenoptera sawflies) in agricultural hedgerows dominated by aggressive non-native plants (novel hedgerows) and hedgerows comprised largely of indigenous plants. It differs from controlled common garden studies because it examines the impact of evolutionarily novel plants that have replaced native plants in unmanaged ecosystems and thus provides a more accurate measure of what is happening to interactions between plants and insects in invaded natural areas. Four hedgerows of each treatment were searched methodically along 100 m transects during June and July 2011 for a seasonal total of 500 min each. Seasonal totals of species richness, caterpillar abundance, and caterpillar biomass were recorded and compared using linear mixed models. We also estimated a Lepidoptera productivity index for each hedgerow based on the plant species composition and biomass as well as literature host records for each species present. Although we found similar richness of plant species, and more plant biomass in novel hedgerows, novel hedgerows had 68% fewer caterpillar species, 91% fewer caterpillars, and 96% less caterpillar biomass than native hedgerows. Moreover, novel hedgerows were predicted to have 5.4 times less Lepidoptera productivity based on their plant composition. Interactions between caterpillars and hedgerow plants were also significantly impacted by introduced plants, with novel hedgerows supporting 84% fewer interactions between plants and caterpillars and 57% less interaction diversity than native hedgerows. This is a considerably larger impact of novel plants on a critical component of terrestrial food webs than has been measured in common garden experiments at the same location and demonstrates that plant-herbivore interactions are compromised when novel species replace resident species, even if plant species richness does not change. [ABSTRACT FROM AUTHOR]

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-21304-2 [ABSTRACT FROM AUTHOR]

Paved roadways, spanning 6.6 million kilometres across the continental United States, are often bordered by natural or restored habitats and could provide opportunities for pollinator conservation. Because insects are frequently killed by auto traffic, roadside habitats may be ecological traps that kill more pollinators than they produce. Here we compare insect traffic mortality when roadsides are bordered by woodlots, meadows, or lawns. We also compare study sites with and without restored medians to examine the impact of creating habitat that can only be accessed by crossing traffic. We confined our study to high speed roads (70-90 km h−1) with heavy traffic volume. Both habitat type and the presence of a vegetated median affect vehicle strikes fatal to insects. Insect mortality in general, and its effect on bees and butterflies in particular, was consistently lower when roads were bordered by woodlots than when they were bordered by lawn or meadows. Which roadside habitats were associated with the highest insect mortality depended on the taxon in question and the presence or absence of a vegetated median. Butterfly and dragonfly mortality was highest on roads with meadow medians, while bee mortality was highest on roadsides with lawn medians. Across most site comparisons, vegetated medians significantly elevated fatal insect-vehicle strikes. Regardless of the habitat bordering roadsides, insect mortality was unacceptably high for areas being considered for conservation. We suggest four research directions that may lead to reduced insect mortality in roadside habitats. [ABSTRACT FROM AUTHOR]

Simple rearing experiments were conducted to address two questions relevant to understanding how generalist lepidopteran herbivores interact with alien plants. Yellow-striped armyworm ( Spodoptera ornithogalli), luna moth ( Actias luna), bagworm ( Thyridopteryx ephemeraeformis) and white-marked tussock moth ( Orgyia leucostigma) were reared from egg to 5th instar on excised foliage in the laboratory to determine the degree to which highly polyphagous lepidopteran herbivores are physiologically capable of surviving and developing on the suite of alien plants naturalized in the mid-Atlantic. Actias luna larvae from a single population were similarly reared on a representative of each of the 25 native plant genera recorded as hosts for this species to compare the diet breadth of a local population with that listed over the entire geographic range of the species. With few exceptions, all four generalists either quickly starved or grew at an unsustainably low rate on alien foliage. Actias luna larvae survived for 18 days on only 44% of the native plants recorded as hosts over the entire range of this insect and thrived on only 7%. The data suggest that (1) alien plants are unlikely to produce as much generalist insect biomass as the native plants they replace and (2) Lepidoptera that qualify as generalists when host breadth is considered over their entire geographic range may express a far more specialized diet within local populations. Both of these conclusions support the hypothesis that alien plant invasions may seriously disrupt terrestrial food webs by reducing the insect biomass required by insectivores in higher trophic levels. [ABSTRACT FROM AUTHOR]

Investigates the proximate factors regulating maternal care and a noncaring, condition dependent strategy called egg dumping using the eggplant lace bug, Gargaphia solani. Time to first oviposition; Females in transition; Comparison of primary oocytes; Nymphal influence on guarding duration; Effect of antennal ablation on guarding duration.

Examines the effect of juvenile hormone or a similarly acting juvenoid on the expression of maternal egg guarding and its life history alternative, egg dumping, in the lace bug, Gargaphia solani Heidemann. Juvenoid treatment; Precocene II treatment.

It is predicted that the intensity of parental defense of offspring is a function of both the increasing reproductive value of offspring and the decreasing reproductive value of parents. The ontogeny of maternal defensive behavior in the lace bug Gargaphia solani is consistent with these predictions in that mothers become more aggressive as they age (between clutches) and also more aggressive as nymphs reach maturity (within clutches). [ABSTRACT FROM AUTHOR]

We describe the first record of amphisexual care in an insect with uniparental male care. Male Rhynocoris tristis are noted for aggressively guarding multiple egg masses. When a male is unable or unwilling to guard eggs, a female that has previously contributed eggs returns to the egg mass and defends it until the eggs hatch. We compared the frequency and intensity of parental aggression in both sexes and found no difference in either form of guarding behavior. Evidence of amphisexual care in R. tristis provides an opportunity to quantify the cost of care in both sexes within a single species. [ABSTRACT FROM AUTHOR]