Spatiotemporal Patterns of Population Decline in Oarisma poweshiek (Hesperiidae) in Michigan and Minnesota Between 1990 and 2013

The recent contraction of the geographic range of Oarisma poweshiek (Poweshiek skipperling) (Lepidoptera: Hesperiidae) resulted in its listing as an endangered species in 2014 (USFWS 2014). However, changes in population density within sites associated with this contraction are still not understood. This range-wide contraction of Poweshiek skipperling appears to indicate a regional cause. Using population data from multiple sites in Michigan and Minnesota, we investigated the temporal and spatial patterns of population decline to determine if regional or site-specific factors likely contributed to the decline. We hypothesized that if regional factors caused the density declines, then the declines would be temporally synchronous and spatially correlated across sites. We found decline patterns to be temporally asynchronous and spatially uncorrelated, except for sites in west-central Minnesota. These results imply that regional factors may not be the main causes for the population density declines, and understanding multiple site-specific factors consistent with observed patterns of decline will be important for recovering Poweshiek skipperling populations

Transgenic Insecticidal Crops and Natural Enemies: A Detailed Review of Laboratory Studies

This review uses a data-driven, quantitative method to summarize the published, peer-reviewed literature about the impact of genetically modified (GM) plants on arthropod natural enemies in laboratory experiments. The method is similar to meta-analysis, and, in contrast to a simple author-vote counting method used by several earlier reviews, gives an objective, data-driven summary of existing knowledge about these effects. Significantly more non-neutral responses were observed than expected at random in 75% of the comparisons of natural enemy groups and response classes. These observations indicate that Cry toxins and proteinase inhibitors often have non-neutral effects on natural enemies. This synthesis identifies a continued bias toward studies on a few predator species, especially the green lacewing, Chrysoperla carnea Stephens, which may be more sensitive to GM insecticidal plants (16.8% of the quantified parameter responses were significantly negative) than predators in general (10.9% significantly negative effects without C. carnea). Parasitoids were more susceptible than predators to the effects of both Cry toxins and proteinase inhibitors, with fewer positive effects (18.0%, significant and nonsignificant positive effects combined) than negative ones (66.1%, significant and nonsignificant negative effects combined). GM plants can have a positive effect on natural enemies (4.8% of responses were significantly positive), although significant negative (21.2%) effects were more common. Although there are data on 48 natural enemy species, the database is still far from adequate to predict the effect of a Bt toxin or proteinase inhibitor on natural enemies

Success of the high-dose/refuge resistance management strategy after 15 years of Bt crop use in North America

Transgenic maize and cotton expressing Bacillus thuringiensis (Bt) toxins were first commercialized in 1996. By 2009, Bt crops were planted on ca. 47.6Mha in 22 countries worldwide, with the USA and Canada accounting for 54% of this area. Resistance (virulence) development in target insect pests is a major threat to the sustainable use of Bt crops. Four major target pests of Bt crops in the USA and Canada - European corn borer, Ostrinia nubilalis (Hübner), southwestern corn borer, Diatraea grandiosella Dyar (both Lepidoptera: Crambidae), tobacco budworm, Heliothis virescens Fabricius (Lepidoptera: Noctuidae), and pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) - remain susceptible to Bt toxins after 15years of intensive use of Bt maize and Bt cotton. The success in sustaining susceptibility in these major pests is associated with successful implementation of the \u27high-dose/refuge\u27 insecticide resistance management (IRM) strategy: (i) Bt crop cultivars express a \u27high dose\u27, (ii) initial frequency of resistance alleles is very low, and (iii) a refuge is maintained nearby in the environment. Field resistance (including control failure) to a Bt crop has been clearly documented in three situations: fall armyworm [Spodoptera frugiperda JE Smith] in Puerto Rico, African stem borer [Busseola fusca Fuller (Lepidoptera: Noctuidae)] in South Africa, and P. gossypiella in India. Factors associated with these cases of field resistance include: failure to use high-dose Bt cultivars and lack of sufficient refuge. These observations support the claim that implementation of the \u27high-dose/refuge\u27 IRM strategy has been successful in substantially delaying field resistance to Bt crops. © 2011 The Authors. Entomologia Experimentalis et Applicata © 2011 The Netherlands Entomological Society

Uncovering trophic interactions in arthropod predators through DNA shotgun-sequencing of gut contents

Characterizing trophic networks is fundamental to many questions in ecology, but this typically requires painstaking efforts, especially to identify the diet of small generalist predators. Several attempts have been devoted to develop suitable molecular tools to determine predatory trophic interactions through gut content analysis, and the challenge has been to achieve simultaneously high taxonomic breadth and resolution. General and practical methods are still needed, preferably independent of PCR amplification of barcodes, to recover a broader range of interactions. Here we applied shotgun-sequencing of the DNA from arthropod predator gut contents, extracted from four common coccinellid and dermapteran predators co-occurring in an agroecosystem in Brazil. By matching unassembled reads against six DNA reference databases obtained from public databases and newly assembled mitogenomes, and filtering for high overlap length and identity, we identified prey and other foreign DNA in the predator guts. Good taxonomic breadth and resolution was achieved (93% of prey identified to species or genus), but with low recovery of matching reads. Two to nine trophic interactions were found for these predators, some of which were only inferred by the presence of parasitoids and components of the microbiome known to be associated with aphid prey. Intraguild predation was also found, including among closely related ladybird species. Uncertainty arises from the lack of comprehensive reference databases and reliance on low numbers of matching reads accentuating the risk of false positives. We discuss caveats and some future prospects that could improve the use of direct DNA shotgun-sequencing to characterize arthropod trophic networks

Biological Invasions: Recommendations for U.S. Policy and Management

The Ecological Society of America has evaluated current U.S. national policies and practices on biological invasions in light of current scientific knowledge. Invasions by harmful nonnative species are increasing in number and area affected; the damages to ecosystems, economic activity, and human welfare are accumulating. Without improved strategies based on recent scientific advances and increased investments to counter invasions, harm from invasive species is likely to accelerate. Federal leadership, with the cooperation of state and local governments, is required to increase the effectiveness of prevention of invasions, detect and respond quickly to new potentially harmful invasions, control and slow the spread of existing invasions, and provide a national center to ensure that these efforts are coordinated and cost effective. Specifically, the Ecological Society of America recommends that the federal government take the following six actions: (1) Use new information and practices to better manage commercial and other pathways to reduce the transport and release of potentially harmful species; (2) Adopt more quantitative procedures for risk analysis and apply them to every species proposed for importation into the country; (3) Use new cost-effective diagnostic technologies to increase active surveillance and sharing of information about invasive species so that responses to new invasions can be more rapid and effective; (4) Create new legal authority and provide emergency funding to support rapid responses to emerging invasions; (5) Provide funding and incentives for cost-effective programs to slow the spread of existing invasive species in order to protect still uninvaded ecosystems, social and industrial infrastructure, and human welfare; and (6) Establish a National Center for Invasive Species Management (under the existing National Invasive Species Council) to coordinate and lead improvements in federal, state, and international policies on invasive species. Recent scientific and technical advances provide a sound basis for more cost-effective national responses to invasive species. Greater investments in improved technology and management practices would be more than repaid by reduced damages from current and future invasive species. The Ecological Society of America is committed to assist all levels of government and provide scientific advice to improve all aspects of invasive-species management

Transfer of Cry1F from Bt maize to eggs of resistant Spodoptera frugiperda

The intergenerational transfer of plant defense compounds by aposematic insects is well documented, and since 2006, has been shown for Cry toxins. Cry toxins are proteins naturally produced by the soil bacterium Bacillus thuringiensis (Bt) and its genes have been expressed in plants to confer insect pest resistance. In this work we tested if non-aposematic larvae of a major maize pest, Spodoptera frugiperda, with resistance to Cry1F, could transfer Cry1F from a genetically engineered maize variety to their offspring. Resistant 10-day-old larvae that fed on Cry1F Bt maize until pupation were sexed and pair-mated to produce eggs. Using ELISA we found that Cry1F was transferred to offspring (1.47–4.42 ng Cry1F/10 eggs), a toxin concentration about 28–83 times less than that detected in Cry1F Bt maize leaves. This occurred when only one or both sexes were exposed, and more was transferred when both parents were exposed, with transitory detection in the first five egg masses. This work is an unprecedented demonstration that a non-aposematic, but resistant, species can transfer Cry1F to their offspring when exposed to Bt host plant leaves as immatures

Integrating adverse effect analysis into environmental risk assessment for exotic generalist arthropod biological control agents: a three-tiered framework

Environmental risk assessments (ERAs) are required before utilizing exotic arthropods for biological control (BC). Present ERAs focus on exposure analysis (host/prey range) and have resulted in approval of many specialist exotic biological control agents (BCA). In comparison to specialists, generalist arthropod BCAs (GABCAs) have been considered inherently risky and less used in classical biological control. To safely consider exotic GABCAs, an ERA must include methods for the analysis of potential effects. A panel of 47 experts from 14 countries discussed, in six online forums over 12 months, scientific criteria for an ERA for exotic GABCAs. Using four case studies, a three-tiered ERA comprising Scoping, Screening and Definitive Assessments was developed. The ERA is primarily based on expert consultation, with decision processes in each tier that lead to the approval of the petition or the subsequent tier. In the Scoping Assessment, likelihood of establishment (for augmentative BC), and potential effect(s) are qualitatively assessed. If risks are identified, the Screening Assessment is conducted, in which 19 categories of effects (adverse and beneficial) are quantified. If a risk exceeds the proposed risk threshold in any of these categories, the analysis moves to the Definitive Assessment to identify potential non-target species in the respective category(ies). When at least one potential non-target species is at significant risk, long-term and indirect ecosystem risks must be quantified with actual data or the petition for release can be dismissed or withdrawn. The proposed ERA should contribute to the development of safe pathways for the use of low risk GABCAs

Biosecurity and Yield Improvement Technologies Are Strategic Complements in the Fight against Food Insecurity

The delivery of food security via continued crop yield improvement alone is not an effective food security strategy, and must be supported by pre- and post-border biosecurity policies to guard against perverse outcomes. In the wake of the green revolution, yield gains have been in steady decline, while post-harvest crop losses have increased as a result of insufficiently resourced and uncoordinated efforts to control spoilage throughout global transport and storage networks. This paper focuses on the role that biosecurity is set to play in future food security by preventing both pre- and post-harvest losses, thereby protecting crop yield. We model biosecurity as a food security technology that may complement conventional yield improvement policies if the gains in global farm profits are sufficient to offset the costs of implementation and maintenance. Using phytosanitary measures that slow global spread of the Ug99 strain of wheat stem rust as an example of pre-border biosecurity risk mitigation and combining it with post-border surveillance and invasive alien species control efforts, we estimate global farm profitability may be improved by over US$4.5 billion per annum