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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2010.03.014 Byline: Jared G. Ali (a), Douglas W. Tallamy (b) Abstract: Using spotted cucumber beetles and their epicuticular hydrocarbon signatures, we examined two hypotheses about how females may use signals that describe a potential mate's immune system to identify high-quality males. Females may find males to be acceptable mates when (1) a male's immune system complements or matches the immune system of the receptive female (immunocompatibility), or (2) a male successfully signals that it has a strong immune system (immunocompetence). The first experiment used gas chromatography to compare the epicuticular hydrocarbon signature of a female beetle with that of a male she rejected and a male she accepted as a mate. We also compared the hydrocarbon signatures of a male and two fertilized females, one that had voluntarily accepted his spermatophore and one that was forced to accept the spermatophore. In both experiments the immune response to an implant inserted in the insect's abdomen was compared in males and their offspring. The hydrocarbon signature of males accepted as mates in the first experiment differed more from that of their female partners than did the hydrocarbon signature of rejected males. There was no significant difference in the immune response of accepted and rejected males. Offspring from forced matings had significantly lower immune responses than offspring from voluntary matings. This study suggests that females use immunocompatibility rather than immunocompetence as a trait to identify quality mates, which fosters stronger immune systems in offspring. Female choice of mates in this species may be self-referenced using the cuticular hydrocarbon signature of the female as a standard. Author Affiliation: (a) Department of Entomology & Nematology, University of Florida, U.S.A. (b) Department of Entomology & Wildlife Ecology, University of Delaware, U.S.A. Article History: Received 4 May 2009; Revised 22 June 2009; Accepted 12 March 2010 Article Note: (miscellaneous) MS. number: A09-00286

An investigation is conducted into the sexual selection of arthropods and the development of paternal care by reducing paternity assurance and increasing promiscuity of males. The results support the theory that in arthropods, certain male behaviours are traits on which sexual selection has acted.

It is difficult to predict maternal care among insects since a number of factors have shaped its development. Maternal care may involve low costs, as in the case of the horsefly. Some insects can breed more than once in a season, and these insects have more to lose by investing in maternal care, since the number of offspring that they can produce is limited. Mothers have greater freedom to invest in offspring if this does not prevent them from breeding again.

A study was conducted to examine whether a chemical deposited by the female lace bug, Gargaphia solani Heidemann, during or shortly after oviposition is a signal for egg dumping. Results showed that egg dumping was more frequent when exposed to chemical extracts from young egg masses and was not stimulated by visual cues. Moreover, the ovipositional chemical used by egg-dumpers is not a way of relocating their eggs.

The richness, abundance, and biomass of phytophagous arthropods like lepidopteran larvae is highly uneven among sympatric tree taxa. Optimal foraging theory predicts that predation pressure will be greatest on foraging substrates that support the highest abundance and/or diversity of prey, thus offering the greatest reward and maximizing fitness. Predation pressure can also vary with the nutritional or energetic needs of predators across the annual cycle. For insectivorous birds, prioritizing foraging effort in trees that support the most insect prey can benefit individuals by improving their foraging efficiency, condition, and ultimately fitness. However, we lack an understanding of how trees vary in their support of bird foraging activity across seasons and among plant taxa. We used plasticine caterpillar models to measure avian predation rates on 9 native North American tree species that vary in caterpillar-hosting potential. We measured avian predation rates during May, June, and October to compare caterpillar mortality in seasons that vary in life- history needs, abundance, and diversity of avian predators. We modeled daily survivorship and total mortality using Cox-proportional hazard models and logistic regression. We found that, across seasons, caterpillars had significantly higher predation rates on trees that are predicted by literature host records to support the most species of caterpillars (β = 0.22 ± 0.05, 95% CI = [0.13,0.32], z = 4.73, P < 0.0001). Caterpillars had the highest mortality in June, coinciding with avian breeding seasons, and the lowest rates in October, coinciding with fall migration and dispersal. Our study suggests that birds disproportionately forage on trees that have the highest potential to support caterpillar richness and presumably prey biomass. The observed pattern of non-random foraging has many implications; for example, the utility of using informed tree selection to improve bird foraging in managed ecosystems or potential negative implications to bird populations of forest-composition shifts due to climate change. Applying this information to habitat restoration will enable land managers to better support avian populations by planting trees that best support foraging substrates for insectivorous birds in managed ecosystems. [ABSTRACT FROM AUTHOR]

1. With evidence of significant global insect declines mounting, urgent calls to mitigate such declines are also increasing. Efforts to reverse insect declines will only succeed, however, if we correctly identify and address their major causes. 2. One potential cause that has received little mention is the global spread of non‐native plants as invasive species, agroforestry products, and ornamental plants. 3. Here we (a) review the theory predicting that most insect herbivores are evolutionarily constrained to use a fraction of available plant lineages; (b) document the extent to which nonnative plants have displaced native plant communities around the globe; (c) examine the evidence that non‐native plants reduce insect abundance and diversity; and (d) suggest guidelines for measuring the impact of non‐native plants on insect populations. 4. We conclude that host range expansions to non‐natives do occur among many insect herbivores but not at the frequency required to prevent insect declines when non‐native plants replace native plant communities. Accordingly, we suggest that curbing the spread and use of non‐ native plants at local, national, and international scales will be a necessary and effective way to reduce some insect declines. [ABSTRACT FROM AUTHOR]

A flurry of recently published studies indicates that both insects and birds have experienced wide-scale population declines in the last several decades. Curiously, whether insect and bird declines are causally linked has received little empirical attention. Here, we hypothesize that insect declines are an important factor contributing to the decline of insectivorous birds. We further suggest that insect populations essential to insectivorous birds decline whenever nonnative lumber, ornamental, or invasive plant species replace native plant communities. We support our hypothesis by reviewing studies that show (1) due to host plant specialization, insect herbivores typically do poorly on non-native plants; (2) birds are often food limited; (3) populations of insectivorous bird species fluctuate with the supply of essential insect prey; (4) not all arthropod prey support bird reproduction equally well; and (5) terrestrial birds for which insects are an essential source of food have declined by 2.9 billion individuals over the last 50 years, while terrestrial birds that do not depend on insects during their life history have gained by 26.2 million individuals, a 111-fold difference. Understanding the consequences of insect declines, particularly as they affect charismatic animals like birds, may motivate land managers, homeowners, and restoration ecologists to take actions that reverse these declines by favoring the native plant species that support insect herbivores most productively. [ABSTRACT FROM AUTHOR]

A study of egg dumping behavior in the lace bug, Gargaphia solani, and the effect of relatedness in the females, shows that dumpers are usually unrelated to recipients under natural conditions. Also, the lace bugs are not discriminatory in their behavior toward unrelated egg dumpers. The recipients provide protection to their own centrally located eggs by receiving a large number of dumpers eggs.

Current guidance on sourcing native plants to support ecosystem function focuses on the high risk of failure when unsuitable material is used in ecological restoration. However, there is growing recognition that risks may be lower and rewards higher at highly disturbed sites isolated from remnant populations, especially when considering support for pollinators, wildlife, and other ecosystem functions. We developed the first decision support tool using expert opinion to assess suitability of different native plant sources, including horticultural cultivars, in two different planting contexts. We assessed the suitability of 761 sources for 72 commonly sold native species in two different planting contexts (small, isolated, highly disturbed sites vs. large, undisturbed sites near remnant populations). Information on genetic and adaptive backgrounds of sources was strikingly lacking, forcing us to exclude one‐third of sources from our assessment. While only 3% of cultivars received high suitability scores for use in large, undisturbed sites near remnant populations, 52% received high suitability scores in small, isolated, highly disturbed sites. However, nearly 25% of cultivars had floral or leaf traits that differed from wild plants in ways that may compromise their ability to support pollinators and other wildlife. Forbs and cultivars lacking genetic diversity and source information were most likely to have altered traits. We recommend that native plant breeders and sellers work together to ensure ecosystem function, adaptation, and diversity information is available to consumers, that consumers request this information to drive demand, and that researchers further investigate how context influences risks and benefits of different sources. [ABSTRACT FROM AUTHOR]

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Human-dominated landscapes represent one of the most rapidly expanding and least-understood ecosystems on earth. Yet, we know little about which features in these landscapes promote sustainable wildlife populations. Historically, in urban areas, landowners have converted native plant communities into habitats dominated by nonnative species that are not susceptible to pest damage and require little maintenance. However, nonnative plants are also poor at supporting insects that are critical food resources for higher order consumers. Despite the logical connection, no study has examined the impact of nonnative plants on subsequent population responses of vertebrate consumers. Here, we demonstrate that residential yards dominated by nonnative plants have lower arthropod abundance, forcing resident Carolina chickadees (Poecile carolinensis) to switch diets to less preferred prey and produce fewer young, or forgo reproduction in nonnative sites altogether. This leads to lower reproductive success and unsustainable population growth in these yards compared with those with >70% native plant biomass. Our results reveal that properties landscaped with nonnative plants function as population sinks for insectivorous birds. To promote sustainable food webs, urban planners and private landowners should prioritize native plant species. [ABSTRACT FROM AUTHOR]