Demography and mass-rearing of Carposina sasakii Matsumura (Lepidoptera: Carposinidae) reared on Golden Delicious and Red Fuji apples in the laboratory

Carposina sasakii Matsumura (Lepidoptera: Carposinidae), is one of the most serious fruit-boring pests in over ten species of fruit trees, and is especially damaging apples in the northern of China. The application of new planting systems, i.e., high-density and dwarfing rootstock orchard systems with mixed apple varieties, makes it important to study the fitness of C. sasakii on these apple varieties to gain fundamental knowledge for use in pest management involving this insect. In this study, life table data of C. sasakii were collected using Golden Delicious and Red Fuji apples as hosts. The egg-larva duration of male C. sasakii reared on Golden Delicious apples (22.81 d) was significantly shorter than that reared on Red Fuji apples (24.27 d). The egg-larva mortality in Golden Delicious apples (59.00%) was lower than that in Red Fuji apples (72.49%). The mortality of the pupal stage, however, was higher in Golden Delicious (10.51%) than in Red Fuji (0%). The total oviposition period (TPOP) on Golden Delicious apples (32.94 d) was significantly shorter than in individuals reared on Red Fuji apples (34.19 d). The intrinsic rate of increase (r = 0.0581 d⁻¹), net reproductive rate (R₀ = 7.57 offspring), and finite rate of increase (λ = 1.0598 d⁻¹) were all higher on Golden Delicious than those on Red Fuji. When the net reproductive rate (R₀) was used, the harvest rate of pupae was higher (0.8678) when reared on Golden Delicious apples than when reared on Red Fuji apples (0.8398). When a large cohort size (n = 200) was used for effective bootstrap sample, the P_E values for C. sasakii reared on Golden Delicious apples and Red Fuji apples were both almost equal to 1. For C. sasakii culturing purposes, Golden Delicious apples would be more productive than Red Fuji.     

Fen mosses can tolerate some saline conditions found in oil sands process water

Mosses are keystone species in peatlands and are an important part of the vegetation of the pre-mined peatlands. Therefore, mosses should be included in rehabilitation projects following oil sands exploitation in north-western Canada. However, mosses growing in post-mined landscapes must tolerate elevated salinity levels found in oil sands process water (OSPW). Knowledge of salinity tolerance and thresholds for fen mosses is needed to place these mosses in the newly created landscapes. We tested the effects of NaCl and Na₂SO₄ on four fen moss species growing in Petri dishes in growth chambers. We simulated two scenarios: (1) four immersion times (¼, 1, 3 and 7 days) in NaCl (0%, 20%, 60% or 100% of the concentration found in OSPW) mimicking periodic flooding and (2) a permanent saline influence (NaCl or Na₂SO₄ alone or in combination at 0%, 30%, 50% or 70% of the concentrations found in OSPW) mimicking situations of high water tables with different contamination levels. The effects on moss growth were estimated by counting new innovations of Bryum pseudotriquetrum, Campylium stellatum, Sphagnum warnstorfii and Tomenthypnum nitens. All tested mosses tolerated saline levels typically found in post-mined landscapes (up to 500 mg L⁻¹ of NaCl and 400 mg L⁻¹ of Na₂SO₄) for up to 100 days of exposure. Short periods of immersion (up to 7 days independently of salt concentrations) induced the production of innovation in non-Sphagnum species, but S. warnstorfii was more rapidly impacted at higher salt concentrations. Short pulses of salt (from 6 h to 7 days) did not influence the formation of new innovations for C. stellatum and T. nitens. Salt type (NaCl and/or Na₂SO₄) had no effect on moss growth. However, a longer exposure (100 days) with saline water, even at low concentrations, diminished the formation of new innovations for B. pseudotriquetrum and T. nitens. C. stellatum was the least affected by salinity and thus we suggest it is the best species to reintroduce in constructed fens.     

Plant functional types and traits as biodiversity indicators for tropical forests: two biogeographically separated case studies including birds, mammals and termites

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.     

Evidence for a recent horizontal transmission and spatial spread of Wolbachia from endemic Rhagoletis cerasi (Diptera: Tephritidae) to invasive Rhagoletis cingulata in Europe

The widespread occurrence of Wolbachia in arthropods and nematodes suggests that this intracellular, maternally inherited endosymbiont has the ability to cross species boundaries. However, direct evidence for such a horizontal transmission of Wolbachia in nature is scarce. Here, we compare the well‐characterized Wolbachia infection of the European cherry fruit fly, Rhagoletis cerasi, with that of the North American eastern cherry fruit fly, Rhagoletis cingulata, recently introduced to Europe. Molecular genetic analysis of Wolbachia based on multilocus sequence typing and the Wolbachia surface protein wsp showed that all R. cingulata individuals are infected with wCin2 identical to wCer2 in R. cerasi. In contrast, wCin1, a strain identical to wCer1 in R. cerasi, was present in several European populations of R. cingulata, but not in any individual from the United States. Surveys of R. cingulata from Germany and Hungary indicated that in some populations, the frequency of wCin1 increased significantly in just a few years with at least two independent horizontal transmission events. This is corroborated by the analysis of the mitochondrial cytochrome oxidase II gene that showed association of wCin1 with two distinct haplotypes in Germany, one of which is also infected with wCin1 in Hungary. In summary, our study provides strong evidence for a very recent inter‐specific Wolbachia transmission with a subsequent spatial spread in field populations.     

Venom gland extract is not required for successful parasitism in the polydnavirus-associated endoparasitoid Hyposoter didymator (Hym. Ichneumonidae) despite the presence of numerous novel and conserved venom proteins

The venom gland is a conserved organ in Hymenoptera that shows adaptations associated with life-style diversification. Few studies have investigated venom components and function in the highly diverse parasitic wasps and all suggest that the venom regulates host physiology. We explored the venom of the endoparasitoid Hyposoter didymator (Campopleginae), a species with an associated polydnavirus produced in the ovarian tissue. We investigated the effects of the H. didymator venom on two physiological traits of the host Spodoptera frugiperda (Noctuidae): encapsulation response and growth rate. We found that H. didymator venom had no significant effect on host cellular immunity or development, suggesting that it does not contribute to parasitism success. The host physiology seemed to be modified essentially by the ovarian fluid containing the symbiotic polydnaviruses. Proteomic analyses indicated that the H. didymator venom gland produces a large variety of proteins, consistent with the classical hymenopteran venom protein signature, including: reprolysin-like, dipeptidyl peptidase IV, hyaluronidase, arginine kinase or allergen proteins. The venom extracts also contained novel proteins, encoded by venom genes conserved in Campopleginae ichneumonids, and proteins with similarities to active molecules identified in other parasitoid species, such as calreticulin, reprolysin, superoxide dismutase and serpin. However, some of these proteins appear to be produced only in small amounts or to not be secreted. Possibly, in Campopleginae carrying polydnaviruses, the host-modifying activities of venom became redundant following the acquisition of polydnaviruses by the lineage.     

Afroprinus cavicola gen. et sp. n. from the Afrotropical region with notes on cave-dwelling Saprininae (Coleoptera,Histeridae)

A new genus and species from Kenya, Afroprinus cavicola is herein described and illustrated and its systematic position is discussed. By the prosternal pre-apical foveae connected by marginal prosternal stria it resembles most of the Afrotropical species of the genus Chalcionellus Reichardt, 1932, or some species of the genus Pholioxenus Reichardt, 1932 from South Africa and Namibia. Afroprinus can be distinguished from Chalcionellus chiefly by the lack of pronotal depressions and a coarsely sculptured, non-metallic dorsum; from Afrotropical species of Pholioxenus it can be most easily distinguished by the asetose pronotal hypomeron. The new taxon was discovered in a cave, but lacks obvious troglophilic adaptations. Notes on other Saprininae taxa found in caves are given. An identification key to the genera of Afrotropical Saprininae is provided.     

Multiple Wolbachia infections in Rhagoletis pomonella

Rhagoletis pomonella Walsh (Diptera: Tephritidae) is a model species for sympatric speciation through host race formation on apple and hawthorn. The bacterial endosymbiont Wolbachia, a manipulator of arthropod reproduction, has been considered to contribute to speciation in several species. A potential role of Wolbachia in sympatric speciation of R. pomonella remains to be tested despite an earlier detection by PCR. In this study, we isolated Wolbachia from R. pomonella individuals from both host species using multi‐locus sequence typing (MLST) and the surface protein wsp. By cloning and sequencing of 311 plasmids, we found sequence types of at least four wPom strains. A complete MLST profile was obtained only for wPom1, whereas MLST loci of the other putative strains were difficult to assign because of multiple infections and low sample numbers. wPom1 occurs in both host races, whereas different sequence types were found at low frequencies only in apple‐infesting R. pomonella. This warrants further investigation as it cannot be excluded that Wolbachia plays a part in this model of sympatric speciation.     

Field observations of visual attraction of three European oak buprestid beetles toward conspecific and heterospecific models

Agrilus biguttatus Fabricius, Agrilus sulcicollis Lacordaire, and Agrilus angustulus Illiger (Coleoptera: Buprestidae) are three beetle species associated with oak trees [Quercus spp. (Fagaceae)] in Europe. In Hungary, all three species were observed in the foliage near freshly cut oak log piles. Agrilus biguttatus was active later in the afternoon, whereas the other species were observed earlier in the day. Dead female models of these three native Agrilus species, as well as the native species Agrilus cyanescens Ratzeburg and the non‐native Agrilus planipennis Fairmaire, were pinned onto adjacent leaves in direct sunlight to observe the visual mating approaches of the local male populations. Agrilus biguttatus and A. sulcicollis males flew toward and landed directly on the models from a distance of 1 m. Agrilus angustulus flew toward the models from a similar distance, but rather than landing directly on a model would alight on the leaf, 1–2 cm away, before walking closer to the model while antennating it. For all three species, there was substantial cross‐attraction to models of other species. Both A. biguttatus and A. sulcicollis males chose A. angustulus models less often than their respective conspecific models. Likewise, A. angustulus males approached A. sulcicollis models less often than their normal conspecific models. Agrilus biguttatus males attempted to copulate with both A. biguttatus and A. planipennis models, afterward remaining with them for several minutes. Agrilus biguttatus males spent more time on A. planipennis models than on conspecific models. Thus, there is substantial cross‐species attraction in visually mediated mating approaches and copulation behavior. These findings suggest a common behavioral template for visual mate‐finding among buprestids and a large degree of close‐range mating compatibility between A. biguttatus and A. planipennis.     

Non-host volatiles mediate associational resistance to the pine processionary moth

An increasing body of evidence indicates that the association between different plant species may lead to a reduction in insect herbivory, i.e. associational resistance. This might be due to a top–down regulation of herbivores by increased numbers of natural enemies or to a disruptive bottom–up influence of lower host plant accessibility. In particular, the richer plant communities release more diverse plant odours that may disturb olfactory-guided host choice and mating behaviour of insect herbivores, i.e. the “semiochemical diversity hypothesis”. However, this hypothesis has been rarely tested experimentally in natural habitats, notably forest ecosystems. We tested the effects of non-host volatiles (NHV) on mate and host location by the pine processionary moth (PPM) at the scale of individual pine trees with branches of non-host tree (birch) at their base. Pheromone trap catches and the numbers of larval nests were both reduced by non-host presence under treated pine trees, confirming an associational resistance mediated by NHV. In both males and females, the antenna could detect several birch volatiles, including methyl salicylate (MeSa). MeSa inhibited the attraction of the PPM male to pheromone traps, as did bark and leaf chips from birch trees. Our test of three doses of MeSa at the habitat scale (50 m forest edges) showed that the reduction in the numbers of male PPM captured in traps and in larval nests was MeSa dose-dependent. These results show that odours released by deciduous non-host trees can reduce herbivory by a forest defoliator in conifers, providing support to the “semiochemical diversity hypothesis” as a mechanism of associational resistance.