Mother-Offspring Relations: Prey Quality and Maternal Size Affect Egg Size of an Acariphagous Lady Beetle in Culture

We investigated mother-offspring relations in a lady beetle Stethorus punctillum Weise that utilizes spider mites as prey. Our objectives were to determine if (1) prey quality affects egg size, (2) maternal size correlates with egg size, and (3) egg size affects hatching success. We fed predators spider mites Tetranychus urticae Koch from lima bean Phaseolus lunatus L. foliage in the laboratory. Mothers of unknown body size offered high rather than low quality spider mites since birth produced larger eggs. Mothers of known body size offered only high quality spider mites, produced eggs of variable size, but mean egg size correlated positively with hind femur length. Mothers laid their eggs singly, rather than in batches, and eggs were large relative to femur size. Egg size did not affect hatch success; mean hatch rate exceeded 95% regardless of egg size. In conclusion, the quality of prey consumed by S. punctillum mothers while in the larval stage can affect their size as adults and, consequently, the size of their eggs. The behavior of laying eggs singly, the positive relationship between maternal size and mean egg size, and the high rate of egg hatch suggest that S. punctillum mothers invest heavily in offspring

A System for Harvesting Eggs from the Pink-Spotted Lady Beetle

We describe a system for harvesting eggs from a predatory insect, the pink-spotted lady beetle, Coleomegilla maculata De Geer (Coleoptera: Coccinellidae). Adult beetles placed in square, transparent containers that included oviposition substrates hanging from the top of the cage deposited eggs on the materials provided. We harvested eggs from these substrates in quantities sufficient for either destructive sampling or synchronous development of larvae. We evaluated effects of crowding inside cages; effects of a chemical attractant on oviposition behavior; egg cannibalism. Females preferred a textured surface rather than a smooth, waxy one for laying eggs. Crowding inhibited oviposition of beetles. Presence of a chemical attractant (methyl salicylate) did not significantly improve oviposition. This paper describes an inexpensive system for harvesting eggs from C. maculata. Refinement of this system should improve oviposition and reduce cannibalism

Limited Transmission of the Ectoparasitic Fungus Hesperomyces virescens

The ectoparasitic fungus Hesperomyces virescens Thaxter (Ascomycota: Laboulbeniales) commonly infects the invasive lady beetle Harmonia axyridis (Pallas) and several other aphidophagous lady beetles in North America and Europe. We tested the hypothesis that bodily contact between adults of different lady beetle species supports horizontal transmission of H. virescens. We used laboratory assays to determine whether H. axyridis or Olla v-nigrum (Mulsant) harboring H. virescens (i.e., source beetles) transmit the fungus to noninfected target beetles H. axyridis, O. v-nigrum, Coccinella septempunctata L., Coleomegilla maculata (De Geer), or Hippodamia convergens Guerin-Meneville. Results indicate that intraspecific transmission (i.e., for the source beetles H. axyridis and O. v-nigrum) was common but interspecific transmission (i.e., from source H. axyridis or O. v-nigrum to target species) was low. Interspecific transmission occurred at low rates from H. axyridis to both C. septempunctata and O. v-nigrum and from O. v-nigrum to both C. septempunctata and H. convergens. Based upon our laboratory assays of forced pairings/groupings of source and target beetles, we predict that horizontal transmission of H. virescens between species of aphidophagous coccinellids is possible but likely rare

A System for Harvesting Eggs from the Pink-Spotted Lady Beetle

We describe a system for harvesting eggs from a predatory insect, the pink-spotted lady beetle, Coleomegilla maculata De Geer (Coleoptera: Coccinellidae). Adult beetles placed in square, transparent containers that included oviposition substrates hanging from the top of the cage deposited eggs on the materials provided. We harvested eggs from these substrates in quantities sufficient for either destructive sampling or synchronous development of larvae. We evaluated effects of crowding inside cages; effects of a chemical attractant on oviposition behavior; egg cannibalism. Females preferred a textured surface rather than a smooth, waxy one for laying eggs. Crowding inhibited oviposition of beetles. Presence of a chemical attractant (methyl salicylate) did not significantly improve oviposition. This paper describes an inexpensive system for harvesting eggs from C. maculata. Refinement of this system should improve oviposition and reduce cannibalism

Predators and parasitoids of the harlequin ladybird, Harmonia axyridis, in its native range and invaded areas

The harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) has rapidly spread in several continents over the past 30 years and is considered an invasive alien species. The success of H. axyridis as an invader is often attributed to weak control by natural enemies. In this paper, we provide an overview of current knowledge on predators and parasitoids of H. axyridis. The common feature of predators and parasitoids is that they directly kill exploited organisms. Currently available data show that H. axyridis, displaying a variety of chemical, mechanical, and microbiological anti-predator defenses, is usually avoided by predators. However, some birds and invertebrates can eat this ladybird without harmful consequences. The primary defenses of H. axyridis against parasitoids include immune response and physiological and nutritional unsuitability for parasitoid development. These defenses are probably relatively efficient against most ladybird parasitoids, but not against flies of the genus Phalacrotophora. The latter are idiobiont parasitoids and hence can evade the host’s immune response. Indeed, rates of parasitism of H. axyridis by Phalacrotophora in the Palaearctic region (both in the native range in Asia and in Europe) are relatively high. While strong evidence for enemy release on the invasive populations of H. axyridis is lacking, several cases of parasitoid acquisition have been recorded in Europe, North America, and South America. We conclude that enemy release cannot be excluded as a possible mechanism contributing to the spread and increase of H. axyridis in the early stages of invasion, but adaptation of parasitoids may lead to novel associations which might offset previous effects of enemy release. However, further work is required to elucidate the population-level effects of such interactions

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Volatile and Non-Volatile Organic Compounds Stimulate Oviposition by Aphidophagous Predators

Introduction: Evidence that volatile organic compounds (VOCs) and non-VOCs stimulate oviposition by aphidophagous predators is scattered throughout the literature. The objectives of this review are to (1) compile records indicating that VOCs and non-VOCs are responsible for oviposition stimulation, (2) calculate an egg production ratio (EPR) for stimulated predators, and (3) determine if EPR is correlated with vapor pressure and molecular weight of active compounds. Methods: The USDA (United States Department of Agriculture), National Agricultural Library, online digital catalog system was used to retrieve abstracts, then the full text of manuscripts on oviposition stimulants for predators. Oviposition-stimulating VOCs and non-VOCS were tabulated with molecular weights and vapor pressure estimates. EPRs were calculated for stimulated coccinellids, syrphids, and chrysopids. Results: Both VOCs and non-VOCs stimulated oviposition behavior by coccinellids and syrphids, but not chrysopids. EPR was greatest for syrphids. Two VOCs, (E)-β-farnesene and 3-methyl-2-butenal, stimulated very high EPR values by the syrphid Episyrphusbalteatus. Regardless of predator taxa, EPR was negatively and positively correlated with molecular weight and vapor pressure, respectively. Conclusions: Syrphids (rather than coccinellids or chrysopids) produce more eggs in response to VOCs. Organic compounds with low-to-moderate molecular weights and moderate-to-high vapor pressures might be most effective oviposition stimulants for aphidophagous predators

Potential of Quercetin to Reduce Herbivory without Disrupting Natural Enemies and Pollinators

Quercetin is one of the most abundant flavonoids in terrestrial plants and pollen. In living plants, quercetin can function as a secondary metabolite to discourage insect herbivory. Literature on insect-quercetin interactions was searched and data synthesized to test the hypothesis that quercetin can become an effective biocide to reduce herbivory without disrupting natural enemies and pollinators. The USDA, National Agricultural Library, DigiTop Navigator platform was used to search the literature for harmful versus nonharmful effects of quercetin on insect behavior, physiology, and life history parameters. Quercetin effects were evaluated on herbivores in five insect orders, natural enemies in two orders, and pollinators in one order. Quercetin was significantly more harmful to Hemiptera, Diptera, and Lepidoptera but significantly more nonharmful to Coleoptera. Harmful and nonharmful effects to Orthoptera were indistinguishable. Quercetin had significantly more harmful (than nonharmful) effects on herbivores when data from the five insect orders were combined. Quercetin concentration (mg/mL) did not significantly affect these results. Quercetin was significantly more nonharmful to natural enemies (Coleoptera and Hymenoptera, combined) and pollinators (Hymenoptera). This study suggests that quercetin could prevent herbivory without disrupting natural enemies and pollinators, but field experiments are necessary to substantiate these results

Effects of Rearing Density on Survival, Growth, and Development of the Ladybird Coleomegilla maculata in Culture

Our research focuses on developing techniques to rear ladybird beetles (Coleoptera: Coccinellidae). We evaluated the effects of rearing density on survival, growth, and development of Coleomegilla maculata. The hypothesis that a low to moderate rearing density has limited or no effects on survival and development was tested. C. maculata first instars were reared to pupae at a density of 1, 5, 10, 15, or 20 individuals per arena (2.5 cm high, 9.0 cm diameter, and 159 cm3 volume) and fed powdered brine shrimp (Artemia franciscana) eggs. More larvae survived at the 1 and 5 densities, but no differences were detected between the 10, 15, or 20 densities. Median survival rate was at least 90% for larvae and 100% for pupae at the 10, 15, and 20 densities. Development time, body weight, and sex ratio were unaffected by rearing density. Overall, this study suggests that C. maculata larvae can be reared successfully at a density of 20 larvae/159 cm3 (≈ 0.126 larvae/cm3) in containers provisioned with powdered A. franciscana eggs. Scaling-up the size of containers, and C. maculata density in these containers, should be possible