Large, ball rolling dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are competitively dominant and can strongly influence community succession in dung pads. Ball production by Scarabaeus sacer Linnaeus was recorded in the Kizilirmak Delta on the Black Sea coast of Turkey by using artificial dung pads from 125 g to 2,000 g. Utilisation of pads across the 16-fold range of pad sizes demonstrated behavioural variation that may reduce intraspecies competition. Ball production was highly concentrated, with 66 balls (61%) produced from 8 pads of the 3 largest pad sizes, which may be related to chemical attraction between males and females. Ball size increased with increasing pad size (P < 0.05) but the number of balls produced per 100 g of dung decreased with increasing pad size (P < 0.01). Pad size for maximum ball production and ball size were 1,371 g and 1,260 g, respectively. The highest and lowest percentage of dung used for ball production was 43% of 125 g pads and 13% of 2,000 g pads, respectively. Ball production and time of day were significantly related (P < 0.01); S. sacer was almost exclusively nocturnal, with 59% of all balls produced between 21.00 and 22.00. This optimum period for ball production early in the night may be a compromise between reduced risk of predation and the increased energy costs of ball production as the temperature falls., Gregory T. Sullivan, Sebahat K. Ozman-Sullivan, Jean-Pierre Lumaret, Myron P. Zalucki, Greg Baxter., and Obsahuje bibliografii
The factors that affect the local distribution of the invasive Harmonia axyridis are not yet completely resolved. Hypotheses predicting positive and independent effects of prey abundance and degree of urbanization on the adult abundance of this species in Central Europe were tested. Populations of H. axyridis were sampled in a period when it was most abundant, by sweeping lime trees (Tilia spp.) at 28 sites along a 20 km transect across urban (western Prague) and surrounding rural areas. The sites differed in aphid abundance (number of Eucallipterus tiliae per 100 sweeps) and degree of urbanization (percentage of the surrounding area within a 500 m radius covered by impervious human constructions). Multiple linear regression analysis of log-transformed data revealed that abundance of H. axyridis (number of adults per 100 sweeps) increased significantly with both aphid abundance (P = 0.015) and urbanization (P = 0.045). The positive relationship between degree of urbanization and abundance of H. axyridis was thus not a side effect of variation in aphid abundance, which was also greater in urban than rural areas. The effect of urbanization might constrict the habitat available to H. axyridis and force this species to aggregate in urban green "refugia". These results point to a plurality of factors that determine coccinellid abundance at natural sites.
For biological control it is necessary to store mass-reared biological control agents when the demand is low. The objective of this study is to increase their shelf life without significantly reducing their fitness. The ladybird Hippodamia variegata is a widespread and voracious aphidophagous predator, with an important role in decreasing the abundance of pest aphids in many parts of the world. We investigated the effect of storage at three temperatures: constant 1°C, constant 6°C, and an alternating thermal regime of 12°C/0°C (the higher temperature for 12 h and the lower one for another 12 h). They were exposed to each of the temperature regimes for either 15, 25, 35, 45 or 60 days. We recorded survival, pre-oviposition period, fecundity and voracity of adult H. variegata following storage. The survival of adult beetles significantly declined with increasing storage duration at all three temperatures. Storage at 6°C up to 35 days and at 12°C/0°C up to 45 days had no significant effects on the fecundity of the ladybirds, but storage for longer significantly decreased fecundity. Beetles stored at 1°C for any of the durations had significantly lower fecundities. Prolonged cold storage caused an increase in the pre-oviposition period at all storage temperatures. Generally, 6°C and 12°C/0°C are the best temperatures for storing the ladybirds as they had the least negative effect on their fitness. The results of this research can help in improving the quality of H. variegata stored for use as biological control agents in the following season.
We investigated the predatory potential and food preference of different life stages of Coccinella septempunctata L. for a nutritious aphid (mustard aphid, Lipaphis erysimi) and toxic aphid (cabbage aphid, Brevicoryne brassicae). We provided all the life stages of C. septempunctata with either L. erysimi or B. brassicae and found that the second, third and fourth instar larvae and adult females of this predator consumed daily greater numbers of L. erysimi. However, the first instar larvae and adult males consumed similar numbers of both of these aphids. In choice condition, each larva, adult males and females were each provided separately with a mixed aphid diet in three proportions (i.e. low: high, equal: equal and high: low densities of L. erysimi: B. brassicae). We hypothesized that life stages of C. septempunctata will prefer L. erysimi regardless of its proportions. Laboratory experiments supported this hypothesis only at the adult level in terms of high values of β and C preference indices. However, it rejects this hypothesis at the larval level, as larvae preferred B. brassicae when provided with certain combinations and showed no preference in a few combinations. We infer that mixtures of nutritious and toxic aphids may enable this ladybird to overcome any probable nutritional deficiency and/or reduce the toxicity of a toxic diet, especially for the larvae. Results of the treatment in which a high proportion of B. brassicae were consumed along with fewer L. erysimi indicates that a mixed diet could be better for the development of immature stages of C. septempunctata., Mushtaq A. Guroo, Ahmad Pervez, Kuldeep Srivastava, Rakesh K. Gupta., and Obsahuje bibliografii
The Asian long-horned beetle, Anoplophora glabripennis, is a serious destructive pest of forests throughout China as it attacks a wide range of host plants. The effect of host trees on the cold hardiness of A. glabripennis larvae could be the basis for predicting the performance of this forest pest on different common hosts.To evaluate the effect of different species of host plant on the cold hardiness of overwintering larvae of A. glabripennis, we measured the supercooling point (SCP), fresh mass, protein content and concentrations of low molecular weight substances in overwintering larvae collected from three different host species (i.e., Populus opera, Populus tomentosa and Salix matsudana). Mean SCPs and protein contents of larvae from these three hosts differed significantly. The SCPs and protein contents of the larvae collected from P. opera and P. tomentosa were significantly higher than those collected from S. matsudana. The concentrations of glycerol, glucose and trehalose in overwintering larvae collected from these host species also differed significantly, but there were no significant differences in the concentrations of sorbitol and inositol. The larvae that were collected from S. matsudana had the highest concentrations of glycerol and trehalose and those from P. opera the lowest contents of glycerol, whereas those from P. tomentosa had the lowest concentrations of trehalose but the highest concentrations of glucose. Because of the significant differences in the quantities of these biochemical substances in their bodies, the cold hardiness of overwintering larvae of A. glabripennis was significantly dependent on the tree they fed on. These effects on the cold hardiness of the overwintering larvae might affect the selection of a host tree and therefore the spread of this beetle. and Yuqian Feng, Reaxit Tursun, Zhichun Xu, Fang Ouyang, Shixiang Zong.
The red flour beetle, Tribolium castaneum, is a pest of stored products. It is also regarded as a model species for studying development, genetics, biology, physiology and biochemistry. Recently, it has become a model for use in RNA interference experiments. 20-hydroxyecdysone (20E) is involved in insect metamorphosis and its role in organ development in T. castaneum are based on hormonal treatment in conjunction with RNAi. However, information on the biological, morphological and physiological effects of 20E on T. castaneum is still limited. This study reveals the responses of T. castaneum larvae to injections with various doses of 20E (100, 200, 300, 400 and 500 ng / insect). The results show that larvae injected with 20E reached the prepupal, pupal and adult stages earlier than the control group. Different degrees of morphological change were observed in nine traits, including the appearance of pupal prothetelic organs in the larvae. Moreover, an injection of a high dose of 20E reduced the body weights of the resulting insects at each stage, as well as the length and width of elytra. The enzymatic activity of α-amylase in the resulting adults also decreased significantly. This indicates that injection of 20E caused precocious metamorphosis in T. castaneum by inducing changes in morphology and α-amylase activity, and the optimal concentrations that induce such phenomena were in the range of 100-200 ng / insect. Further investigations are needed to examine the roles of 20E in the regulation of α-amylase in T. castaneum., Nujira Tatun, Phiraya Kumdi, Jatuporn Tungjitwitayakul, Sho Sakurai., and Obsahuje bibliografii
A variety of plant protection products and other agrochemicals are used in agro-ecosystems. Products approved for integrated pest management (IPM) or organic farming should have minimal negative side effects on benefi cial insects. The Asian harlequin ladybird Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) has become a widespread and important generalist predator of certain agricultural pests, mainly aphids, throughout Europe. We studied the effects of two agrochemicals, Boundary SW® (auxiliary plant protection product) and Prev B2® (foliar boron fertilizer), usually regarded as “environmentally friendly” and known to have insecticidal side effects against some fruit and vegetable pests (e.g., aphids, spider mites, weevils), on the last larval instar and adults of Harmonia axyridis. The conventional organophosphate insecticide Reldan 22® was used as a chemical standard for evaluating the lethal effect, because this product is usually effective against a broad spectrum of insects, and indeed was immediately lethal for both the adults and larvae of this species. However, whereas Prev B2® had no effect, adult ladybirds sprayed with Boundary SW® survived only for up to 25 h and also none of the larvae completed their development. Thus, although our experiments were not made under natural conditions, the use of Boundary SW® cannot be recommended for IPM and organic farming in terms of safeguarding insect predators such as Harmonia axyridis until further more detailed testing.
The maize weevil, Sitophilus zeamais (Motschulsky), is a major pest of stored grain kernels. Irradiation is an established technique for controlling insects in stored grain and is a major stress factor affecting these insects. Since heat shock protein (hsp) genes respond to this stress, we proposed that hsps may be associated with irradiated stress tolerance in S. zeamais. The responses of the maize weevil to exposure to ultraviolet-C (UV-C) and microwave irradiation were assessed at four developmental stages: egg, larva, pupa and adult. The results revealed that exposure to UV-C (254 nm, < 8 h) did not affect the survival of the maize weevils; however, Szhsp70, Szhsc70 and Szhsp90 mRNA levels significantly increased during the first 1 h of UV-C exposure. The median lethal time (LT50) of exposure to microwave irradiation indicated that the adult stage was more tolerant of microwave irradiation than the other developmental stages. Microwave irradiation enhanced the expression of the three hsps, but the intensity of up-regulation differed among the three genes, with Szhsp70 the most highly up-regulated. Our experiments revealed that UV-C and microwave irradiation influenced the expression profile of hsp genes in S. zeamais. At the tissue level, the gene responses to UV-C and microwave irradiation varied greatly in different tissues., Jatuporn Tungjitwitayakul, Nujira Tatun, Boongeua Vajarasathira, Sho Sakurai., and Obsahuje bibliografii
Traps baited with plant volatiles and/or bark beetle pheromones have been used to survey for exotic and potentially invasive bark and wood-boring beetles in North America since the mid-1990s. Recent discoveries of sex and aggregation pheromones in the Cerambycidae offer means of improving detection rates of longhorn beetles, but little is known of their effects on detection of bark and ambrosia beetles in the subfamily Scolytinae. Our objectives were to determine the efficacy of host volatile trap lures for survey and detection of Scolytinae species and whether that efficacy was affected by the addition of longhorn beetle pheromones. More than 12,000 specimens and 36 species of Scolytinae were collected in two field trapping bioassays conducted in the Russian Far East in 2009 and 2010. The lure combination of spruce blend (a blend of racemic α-pinene, (-) β-pinene, (+)-3-carene, (+)-limonene, and α-terpinolene) and ethanol significantly increased detection rates and mean catches of Hylastes brunneus Erichson, Hylastes obscurus Chapuis, Ips typographus (L.), and Dryocoetes striatus Eggers compared with unbaited traps. The addition of the longhorn beetle pheromones, E-fuscumol, or E-fuscumol acetate, to traps baited with spruce blend and ethanol, slightly reduced mean catches of D. striatus but otherwise did not affect catch of any Scolytine species. Baiting traps with ethanol significantly increased mean catches of Anisandrus apicalis (Blandford), Anisandrus dispar (Fabr.), Anisandrus maiche (Kurenzov), Xyleborinus attenuatus (Blandford), Xyleborinus saxesenii (Ratzeburg), Xylosandrus germanus (Blandford), Scolytoplatypus tycon Blandford, and Trypodendron lineatum (Olivier). By themselves, the longhorn beetle pheromones, racemic hydroxyhexan-2-one and racemic hydroxyoctan-2-one, were not attractive to any Scolytine species. However, when added to ethanol-baited traps, hydroxyhexan-2-one lures significantly increased mean catch of S. tycon, hydroxyoctan-2-one lures significantly reduced mean catches of A. maiche and X. attenuatus, and lures of either hydroxyketone significantly reduced mean catch of T. lineatum. The lure treatments that detected the greatest number of species per sampling effort were spruce blend plus ethanol in 2009 (16 Scolytinae species and 13 species of Cerambycidae combined in an eight-trap sample) and hydroxyhexan-2-one plus ethanol in 2010 (20 Scolytinae species and 7 species of Cerambycidae combined in an eight-trap sample). Species accumulation curves did not reach an asymptote for any lure treatment, indicating that many species would go undetected in samples of 8-9 traps per site., Jon D. Sweeney, Peter Silk, Vasily Grebennikov, Michail Mandelshtam., and Obsahuje bibliografii
To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profi les) were compared in terms of their size (area under the seasonal profi le curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profi les varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profi les revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this fl exibility is an important factor in its invasive success.