Population statistics and biological traits of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) affected by LC30 of thiamethoxam and pirimicarb

Although selective pesticides are recommended to use in integrated pest management (IPM) programmes, they could adversely affect biological agents. So, the aim of the current study was to investigate the LC₃₀ of pirimicarb and thiamethoxam on Hippodamia variegata. Two pesticides, pirimicarb and thiamethoxam, when applied at concentrations of 1522.8 and 251.3?mg (ai)/L, respectively, on the third instar larvae of the insect, produced 30% mortality. Also, results showed that neither pirimicarb nor thiamethoxam affect stage age distribution (c_x), fecundity (eggs/female) and adult development time. These two pesticides extended preadult duration significantly (p?<?0.0001, F?=?31.22, df?=?122). Also, survival rate (l_x) and age-specific reproductive value (v_x) decreased and some changes in age-specific life expectancy (e_x) happened. Generally, more adverse effects were found in the population treated by thiamethoxam. The results showed that pirimicarb and thiamethoxam have potential to harm the predatory ladybird in IPM programme, though in sublethal doses.     

Patterns of morphological and genetic diversity of Valeriana jatamansi Jones in different habitats and altitudinal range of West Himalaya,India

Importance to know and understand diversity of Himalayan plants is increasingly recognized considering the fact that various natural and anthropogenic pressures might bring about serious influences to morphological and genetic diversity of the vegetation in the region. In this context, Valeriana jatamansi was investigated in detail, taking into account its importance in various Ayurvedic and modern medicines. Randomly selected mature plants from twenty five different populations (located between 1215 m to 2775 m asl) of V. jatamansi were analysed for their morphological attributes. Further, ISSR markers were used to detect genetic variation among 151 plants of selected 25 populations. Use of 20 primers yielded 125 reproducible polymorphic loci which were used to estimate different parameters of genetic diversity. These parameters were in turn applied to develop relationships with habitat types and altitude range. Significant variation (p < 0.05) in above ground dry weight (AGDW) and below ground dry weight (BGDW) across the populations was observed. Nei's genetic diversity index (He) ranged from 0.25 to 0.37 across the populations, with a mean of 0.31. Genetic diversity exhibited a decreasing trend with increasing altitude, and maximum diversity (He = 0.325) was observed in the range of 1201–1500 m asl. Among the different habitat conditions, highest genetic diversity (He = 0.334; Pp = 84.38) was observed in grassland habitats while minimum in mixed forest habitats (He = 0.285; Pp = 72.433). The genetic diversity (He) had significant negative relationships with AGDW, BGDW and rhizome diameter (Pearson r = −0.359, −0.424 and −0.317, respectively; p < 0.05). The genetic characterization of V. jatamansi from the western Himalaya by this study suggests influences of habitat types and the altitudinal range upon genetic diversity, and based on these proposals for conservation strategies in favour of the species are made.     

cDNA cloning,expression, and enzymatic activity of a novel endogenous cellulase from the beetle Batocera horsfieldi

In this study, we report a novel cellulase [β-1,4-endoglucanase (EGase), EC 3.2.1.4] cDNA (Bh-EGase II) belonging to the glycoside hydrolase family (GHF) 45 from the beetle Batocera horsfieldi. The Bh-EGase II gene spans 720 bp and consists of a single exon coding for 239 amino acid residues. Bh-EGase II showed 93.72% protein sequence identity to Ag-EGase II from the beetle Apriona germari. The GHF 45 catalytic site is conserved in Bh-EGase II. Bh-EGase II has three putative N-glycosylation sites at 56–58 (N–K–S), 99–101 (N–S–T), and 237–239 (N–Y–S), respectively. The cDNA encoding Bh-EGase II was expressed in baculovirus-infected insect BmN cells and Bombyx mori larvae. Recombinant Bh-EGase II from BmN cells and larval hemolymph had an enzymatic activity of approximately 928 U/mg. The enzymatic catalysis of recombinant Bh-EGase II showed the highest activity at 50 °C and pH 6.0.     

Evolution of nesting behaviour and kleptoparasitism in a selected group of osmiine bees (Hymenoptera: Megachilidae)

The construction of nests to rear offspring is restricted to vertebrates and few insect taxa, such as termites, wasps, and bees. Among bees, species of the family Megachilidae are characterized by a particularly high diversity in nest construction behaviour. Many megachilid bees nest in excavated burrows in the ground, others place their brood cells in a variety of above‐ground cavities or attach them to the surface of a substrate, and yet others have adopted a kleptoparasitic habit. Evolutionary transitions between the different nesting sites and between conventional nesting and kleptoparasitism in bees are poorly understood. In the present study, we traced the evolution of nesting site selection and kleptoparasitism in the Annosmia–Hoplitis group (Osmiini), which displays an exceptionally high diversity in nesting behaviour. We found that the evolution of nesting behaviour proceeded unidirectionally from nesting in excavated burrows in the ground to nesting in rock depressions and cavities, followed by the colonization of snail shells and insect borings in dead wood or hollow stems. Kleptoparasitism evolved once and the kleptoparasitic species have derived from the same lineage as their hosts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108 , 349–360.     

Effects of learning experience on behaviour of the generalist parasitoid Sclerodermus pupariae to novel hosts

Massicus raddei Blessig (Coleoptera: Cerambycidae), also referred to as the oak long‐horned beetle (OLB), is a non‐natural host for the generalist parasitoid Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae). To determine whether this generalist parasitoid might be a suitable agent for the control of OLB, the adaptive learning experience of adult female parasitoids to OLB larvae was investigated in the laboratory. A Y‐tube olfactometer bioassay was used to examine the effects of adaptive learning experience on the foraging ability of parasitoids for OLB larvae. The results indicated that parasitoids were significantly attracted by the volatiles of ash bark, Fraxinus velutina, with emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) larvae and larval frass, after exposure to ash bark mixed with EAB larval frass (learning condition A). In contrast, after exposure to oak bark, Quercus liaotungensis, mixed with OLB larval frass (learning condition C), parasitoids showed significant preference for the volatiles of oak bark with OLB larvae and larval frass. On the basis of the results of no‐choice tests, we found that parasitoids exposed to learning condition C had greater paralysis efficiency and higher OLB larvae parasitism rates than those exposed to learning condition A or no experience. Furthermore, parasitoids fed on OLB larvae in learning condition C had significantly greater paralysis efficiency and higher OLB larvae parasitism rates than other parasitoids tested. Parasitoids fed on EAB larvae in learning condition A had the lowest paralysis efficiency and OLB larvae parasitism rates among the parasitoids tested. These findings suggested that adaptive learning significantly enhanced the ability of a generalist parasitoid to utilize a novel host. This may provide a new approach to controlling non‐natural hosts using generalist parasitoids.     

The genera Stegastopsis Kraatz, 1865 and Orostegastopsis Koch, 1962 with description of O. planioculata sp. n. from Oman (Coleoptera: Tenebrionidae: Tentyriini)

The first Asian member of Orostegastopsis Koch, 1962 Koch, C. (1962): Vierter taxonomischer Beitrag zur Kenntnis der Tenebrioniden Somalias: Über die von Prof. G. Scortecci 1953 und 1957 in der Migiurtinia-Provinz gesammelten Arten. 1. Teil. Atti della Società Italiana di Scienze Naturali, 51, 237–270. [Google Scholar] is described and figured: O. planioculata sp. n., which can be easily distinguished from the two Somalian species O. scorteccii Koch, 1962 Koch, C. (1962): Vierter taxonomischer Beitrag zur Kenntnis der Tenebrioniden Somalias: Über die von Prof. G. Scortecci 1953 und 1957 in der Migiurtinia-Provinz gesammelten Arten. 1. Teil. Atti della Società Italiana di Scienze Naturali, 51, 237–270. [Google Scholar] and O. kaszabi (Bremer, 1985 Bremer, H. J. (1985): Eine neue Stegastopsis-Art (Coleopt., Tenebrionidae, Tentyriini) aus Somalia. Entomologische Blätter, 81, 59–61. [Google Scholar]) comb. nov. by the shallow eyes. According to the shape of the clypeus, Stegastopsis kaszabi Bremer, 1985 Bremer, H. J. (1985): Eine neue Stegastopsis-Art (Coleopt., Tenebrionidae, Tentyriini) aus Somalia. Entomologische Blätter, 81, 59–61. [Google Scholar] is transferred from the genus Stegastopsis Kraatz to the genus Orostegastopsis Koch as was already indicated by Bremer (1985 Bremer, H. J. (1985): Eine neue Stegastopsis-Art (Coleopt., Tenebrionidae, Tentyriini) aus Somalia. Entomologische Blätter, 81, 59–61. [Google Scholar]) who treated Orostegastopsis as a subgenus of Stegastopsis: Orostegastopsis kaszabi (Bremer, 1985 Bremer, H. J. (1985): Eine neue Stegastopsis-Art (Coleopt., Tenebrionidae, Tentyriini) aus Somalia. Entomologische Blätter, 81, 59–61. [Google Scholar]) comb. nov. Keys to the species of Stegastopsis and Orostegastopsis are given.     

Metabolism of Thiophene-2-carboxylate by a Photosynthetic Bacterium

A photosynthetic bacterium, which can grow photosynthetically on benzoate, was isolated from sewage mud. Various kinds of aromatic compounds including heterocyclic aromatic compounds were photometabolized by the washed cells grown photosynthetically on benzoate with no lag period. Among these, thiophene-2-carboxylate was metabolized most rapidly to its (+)-tetrahydro derivative. The same strain could also grow on succinate under photosynthetic conditions. However, thiophene-2-carboxylate was only photometabolized after a long lag period by the washed cells grown photosynthetically on succinate, and the metabolite was not its (+)-tetrahydro derivative but (+)-3-hydroxytetrahydrothiophene-2-carboxylate. In the presence of chloramphenicol, an inhibitor of protein synthesis, the photometabolism of thiophene-2-carboxylate by the washed cells grown photosynthetically on benzoate was not affected at all, but the photometabolism of the same substrate by the washed cells grown photosynthetically on succinate was completely inhibited. These results indicate that a reduction system of broad substrate specificity for aromatic rings is already present in the benzoate-grown cells but absent in the succinate-grown cells. It seems that such a reduction system for aromatic rings is induced by an aromatic substrate.     

Phase control of circadian activity in the antelope ground squirrel

Abstract

Wheel‐running activity of forty antelope ground squirrels, Ammospermophilus leucurus, was monitored for several months in both an outdoor cage and in the laboratory. The squirrels demonstrated a highly diurnal pattern which persisted in “constant conditions.” After removal from the field the initial free‐running period was close to 24 hrs, but typically lengthened in a nearly linear fashion at least for the first few months. There was no evidence of any difference in this trend for squirrels, in D/D, L/L 100 lx, 250 lx or 1200 lx. Eventually, about 90 percent of the squirrels had periods longer than 24 hrs.

The synchronizing capacity of the natural photoperiod was used to “catch the free‐running rhythm” and thereby demonstrate a response curve. Synchronization occurred by a shortening of the period when the time of sunrise was between 125° and 0° (subjective night) and by a lengthening of the period when the time of sunrise was between 0° and 125° (subjective day).

To more thoroughly examine the underlying mechanisms of phase control, phase‐response curves based on sixty one light‐pulse experiments were constructed. Comparisons of curves based on 6‐hr and 15‐min pulses, showed that the integral action of light is important (i.e., the entire pulse is involved in phase shifting). It was found that light pulses not only affected the phase of the rhythm but also the phase. Large phase shifts were usually associated with decreases in free‐running period. Several hypotheses on the controlling mechanisms were advanced.     

Saccharide-mediated antagonistic effects of bark beetle fungal associates on larvae

Bark beetles are among the most destructive of pine forest pests and they form close symbiotic relationships with ophiostomatoid fungi. Although some fungi are considered to be mutualistic symbionts of bark beetles with respect to the supply of nutrients, detrimental effects of fungal symbionts on larval growth have also been frequently reported. The mechanisms of such antagonistic effects are hypothesized to be a decrease in nutritional resources caused by competition for saccharides by the fungi. Here, we provide experimental evidence that three beetle-associated fungi modify the nutritional content of an artificial phloem diet, leading to a detrimental effect on the growth of Dendroctonus valens larvae. When larvae were fed a diet of pine phloem in agar medium colonized with any of these fungi, feeding activity was not affected but weight significantly decreased. Additional analysis showed that fungi depleted the fructose and glucose concentrations in the phloem media. Furthermore, these detrimental effects were neutralized by supplementing the media with fructose or glucose, suggesting that fungi may affect larval growth by modifying diet saccharide contents. These data indicate that fungus-induced nutritional changes in bark beetle diet can affect larval growth, and that the mechanism involves fungus-induced saccharide depletion from the larval diet.