Satellite DNAs are the major repetitive DNA components in eukaryotic genomes. Although satellite DNA has long been called "parasite DNA" there is substantial evidence that it could be associated with some functions of chromosome biology. Ladybird beetles (Coccinellidae) are one of the largest and most important groups of beetles. Many ladybirds are of economic interest as biological control agents because they eat some agricultural pests such as aphids and scale insects. However, other species are phytophagous and can damage crops. Despite the ecological importance of the latter group there are no studies on their satellite DNA. A satellite DNA family was isolated and characterized in the ladybird Henosepilachna argus. This satellite DNA is organized in tandem repeats of 658 bp and is A + T rich (67.3%). The recorded high sequence conservation of the monomers together with the detection of putative gene conversion processes indicate concerted evolution. Reverse transcription polymerase chain reaction (RT-PCR) revealed that this satellite DNA is transcribed and in situ hybridization its location in the subtelomeric regions of all chromosomes except the long arm of the X chromosome. The presence of this satellite DNA in other species of the genus Henosepilachna and Epilachna was also tested using PCR. The results indicate that this satellite DNA sequence is so far specific to H. argus., Pablo Mora, Jesús Vela, Areli Ruiz-Mena, Teresa Palomeque, Pedro Lorite., and Obsahuje bibliografii
Dinocampus coccinellae is a parasitoid wasp usually parasitizing ladybird beetles of the tribe Coccinellini. A field survey conducted between March and November 2016 revealed three hosts of this parasitoid in the Srinagar district of the Indian state of Jammu and Kashmir: two members of the Coccinellini (Oenopia conglobata and Coccinella undecimpunctata) and one of the Chilocorini (Priscibrumus uropygialis). Proportion of the latter (atypical) host that were parasitized was 0.09 and intermediate between that recorded for C. undecimpunctata (0.06) and O. conglobata (0.14). A series of laboratory experiments revealed that while a member of Coccinellini (O. conglobata) was more often attacked by D. coccinellae than a member of Chilocorini (P. uropygialis), the proportions of each species from which parasitoids emerged did not differ significantly. There were no significant differences between D. coccinellae females bred from O. conglobata and P. uropygialis, with respect to selection of the two host species and their suitability for the development of the parasitoid. However, members of the Chilocorini other than P. uropygialis (Chilocorus infernalis and Simmondsius pakistanensis) were rarely attacked by D. coccinellae and parasitoid larvae did not emerge from any of those attacked. The results of our experiments indicate that in Kashmir Himalayas D. coccinellae is adapted to parasitize hosts belonging to both Coccinellini and Chilocorini., Amir Maqbool, Imtiaz Ahmed, Piotr Kiełtyk, Piotr Ceryngier., 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
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.
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.
Coccinellids are effective predators and a key component of the predator guild in rice ecosystems. In order to enhance their efficacy, a study was undertaken to assess the seasonal movement of coccinellids into rice fields and the role of the surrounding flora on their colonization. The seasonal abundance of coccinellids and their prey was recorded on the rice crop and the surrounding flora at fortnightly intervals from 2012 to 2015. Coccinellid prey range was assessed using PAGE electrophoresis. The herbivorous insects associated with weeds were Aphis gossypii Glover, Aphis craccivora (Koch), Cicadulina bipunctata (Melichar), Schizaphis graminum (Rondani), Sitobion sp., Thaia oryzivora Ghauri and Zygina maculifrons Matsumura. Of the species of coccinellids recorded in rice fields, Harmonia octomaculata (Fabricius), Micraspis discolor (F.), Propylea dissecta (Mulsant), Coccinella transversalis Fabricius, Cheilomenes sexmaculata (Fabricius), Scymnus nubilus Mulsant and Brumoides suturalis (Fabricius) were also recorded on weeds. The esterase profiles indicated that the leafhoppers and aphids on the weeds were the prey of the coccinellids before they colonized the rice fields. The coccinellids recorded on the weeds showed bands corresponding to the insects present on the weeds. Beetles collected from rice fields had different bands, some of which corresponded to the green leafhopper (GLH) Nephotettix virescens Distant, the brown planthopper (BPH) Nilaparvata lugens Stal and white backed planthopper (WBPH) Sogatella furcifera Hovarth infesting rice. In addition, some bands corresponded to hoppers and aphids that were present on the surrounding flora. The results indicate the importance of surrounding flora in the conservation and colonization of rice fields by coccinellids., Chitra Shanker, Lydia Chintagunta, Sampathkumar Muthusamy, Sunil Vailla, Amudhan Srinivasan, Gururaj Katti., and Obsahuje bibliografii
In the last two decades a huge amount of research has focused on the invasive harlequin ladybird, Harmonia axyridis, particularly on potential or actual deleterious effects that have arisen after it has colonised new regions. A focus of this work has been real or anticipated declines in native ladybird abundance since the introduction of H. axyridis, for which it is deemed responsible. Scientists have generally painted a very bleak picture of the effects of H. axyridis on native species: in this paper I argue that the picture painted is often too bleak. I use the case of the 2-spot ladybird, Adalia bipunctata, the species most often invoked as threatened by H. axyridis, to illustrate my point. While there is little question that H. axyridis has led to a decline in A. bipunctata populations in Europe, it seems likely that prior to the invasive ladybird's arrival A. bipunctata occurred in artificially high numbers in the urban environments in which it was typically studied. Pollution in towns and cities led to enhanced numbers of prey aphids on plants there which initially favoured A. bipunctata, and later H. axyridis. Thus one species, A. bipunctata, that has benefitted from an association with humans has been replaced by another, H. axyridis, just as brown rats replaced black rats in Europe and North America. Viewed with a longer perspective, A. bipunctata has more likely declined back to pre-industrial levels: the artificially high level from which it has declined recently was not a 'natural' one, and thus its decline from this level does not imply that it is now threatened or endangered. More broadly, we need a wider perspective, encompassing other ladybirds, longer timeframes and better comparisons with other (non-ladybird) invasive species to more clearly assess whether H. axyridis really poses as much of a threat as is often proposed., John J. Sloggett., and Obsahuje bibliografii
Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Hemiptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverflies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfly species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may reflect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators., Elise A. Rocha, Estevão N.F. Souza, Lewis A.D. Bleakley, Christopher Burley, Jade L. Mott, Gloria Rue-Glutting, Mark D.E. Fellowes., and Obsahuje bibliografii