Fourteen predatory species of ladybirds (Coleoptera: Coccinellidae) were collected from May to October 2008 from mountain ash (Sorbus aucuparia) infested with the scale insect Chionaspis salicis at 31 localities in the Ore Mountains, northern Bohemia, Czech Republic. Chilocorus renipustulatus, usually a rare species, made up 85% of the individuals collected (1690). Other abundant species were Coccinella septempunctata, Calvia quatuordecimguttata, Adalia bipunctata and Adalia decempunctata. The invasive alien Harmonia axyridis was present but made up less than one per cent of the individuals collected. Niche overlap between pairs of ladybird species measured in terms of the coefficient of community, Morisita's index and cluster analysis showed that microhabitat preferences were similar and hence the possibility of competition was high in two pairs of congeneric species (Chilocorus and Calvia). Larvae of Ch. renipustulatus were abundant from mid-June through August and were still present in October. and Emanuel Kula, Oldřich Nedvěd.
Two blacklight traps were operated in a non-agricultural setting in Cary, North Carolina, USA, from spring through fall in 2004 and 2005 and all Coccinellidae collected and identified. More than 1300 lady beetles were collected in each of the two years, with Harmonia axyridis dominant (> 98%) and collected consistently over the course of the trapping period. Although other coccinellid species were observed in the vicinity of the traps during photophase, their appearance in blacklight traps was negligible. Harmonia axyridis exhibited a distinct diel periodicity in appearance at the traps, beginning approximately an hour after sunset and ending about midnight. Sunrise and sunset collections from flight interference and sticky traps in a local alfalfa field suggest that H. axyridis may be more flight active during the scotophase than Coleomegilla maculata, Hippodamia convergens, and Coccinella septempunctata. This study supports the suggestion that blacklight traps give a biased depiction of coccinellid species composition in a given area, and indicates that seasonal and circadian thresholds for flight activity, phototaxis, or both in H. axyridis may diverge from those in most other Coccinellidae., Christine A. Nalepa., and Obsahuje seznam literatury
During the past four decades, several species of aphidophagous Coccinellidae became established in North America, including Coccinella septempunctata, Harmonia axyridis, Hippodamia variegata, and Propylea quatuordecimpunctata. After their
establishment, unknown circumstances favoured a rapid increase in population densities and distribution of H. axyridis and C. septempunctata at localities hundreds and thousands of kilometers from their release sites. Propylea quatuordecimpunctata and Hippodamia
variegata have spread more slowly after becoming established in northeastern North America. Comparative studies based
upon allozyme variation in these four introduced species and in six native North American species of ladybird beetles revealed no
significant differences in genetic diversities. Genetic variation, assessed by allelic diversity and heterozygosity, was uncorrelated
with the establishment and spread of these predatory species in North America. All ladybirds studied show a remarkable degree of
dispersion with little detectable population subdivision.
The incidence of sibling cannibalism in clutches of Harmonia axyridis infected by the male-killing Spiroplasma was compared with that in uninfected clutches, and the way in which fitness compensation was realized by sibling cannibalism was investigated. Primarily the rate of sibling cannibalism was determined by the hatching rate as all unviable eggs were consumed both in infected and uninfected clutches. Per capita consumption of roughly 0.1 individuals was estimated for uninfected clutches in the present study, as compared to 0.3 individuals in previous studies. The per capita consumption in infected clutches was 1.4, showing that the male-killing behavior of the Spiroplasma provides an approximately 4-14 fold increase in the chance of sibling cannibalism. Both in infected and uninfected clutches, the median of the starting time of sibling cannibalism was soon after that of the completion of hatching. Larvae started to disperse from their egg clutches only about 7.5-8.5 h after the initiation of hatching. These time sequences indicate that sibling cannibalism occurs at the earlier stage of the hatching process and the density of aphids in the area has little or no influence on incidence of the sibling cannibalism. During the maintenance of the infected line for five generations, exclusively females were produced and the median of the hatching rate was 0.395, suggesting a very high rate of vertical transmission of the Spiroplasma infection. Although the measurement of other parameters, such as the effect of Spiroplasma infection on fecundity or longevity, are necessary, the high compensation rate shown in the present study, together with the very high vertical transmission, may explain the prevalence of the present male-killing agent in the local populations of the ladybird beetle.
Certain alkanes or their mixture present on the surface of ladybird elytra is important in the recognition of potential mates. Similar chemicals are present in the tracks of larvae, which deter conspecific female ladybirds from laying eggs in aphid colonies already being attacked by larvae. Finally, the shell of ladybird eggs is covered with alkanes that deter other species of ladybirds from eating the eggs. In each case the alkanes are similar although they fulfil different functions. There are, therefore, indications that ladybirds exploit their natural product with parsimonious versatility.
The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe. In the present study we test this idea of a short, early period of diapause by sampling beetles from their hibernation sites immediately after their migratory flights in October, subsequently keeping them in outdoor cages, and then, after certain time-intervals, measuring the pre-oviposition time under optimal egg-laying laboratory conditions at 25°C. We did this at both short (12L) and long (16L) photoperiods, since a photoperiodic response is an indicator of true diapause, rather than quiescence. A significant, albeit small, difference in pre-oviposition period between the two photoperiods, which disappears in December, corroborates our earlier hypothesis that the ladybirds are in a state of diapause until mid-December. Compared with that of native ladybirds the diapause of H. axyridis generally is relatively short and weak; moreover, it appears to have become shorter over the last decade. This flexibility in diapausing behaviour may be an important factor that contributes to the invasive success of H. axyridis., C. Lidwien Raak-Van Den Berg ... [et al.]., and Obsahuje seynam literatury
The use of light traps for controlling insect pests is restricted since they kill both pests and beneficial insects. It may be a possible to reduce the numbers of beneficial insects trapped by adjusting nightly trapping time based on differences recorded in the timing of the nocturnal flight peaks of target pests and beneficials. To test this, insects were collected hourly over night using black light traps at three locations in China from 2003 to 2005. Groups of lepidopteran and coleopteran pests were selected as the target pests that we would control by trapping and groups of beneficial predatory insects the catches of which needed to be reduced. The highest numbers of Coleoptera were caught between 20:00 and 22:00 h and of most Lepidoptera between 02:00 and 04:00 h. The hourly numbers of predatory insects caught by light traps were evenly distributed throughout the night. A model was developed to describe the relationships between the cumulative proportions of insects caught and time of night. The model accurately describes the flight activity of insects that were mainly caught before midnight, after midnight and evenly throughout a night by using different parameters for the three different insect groups. A beneficial-friendly trapping strategy was developed to reduce the numbers of beneficial insects trapped, which was based on differences in the nocturnal flight activity of pests and beneficial insects and validated by a field study in Shandong province. Results show that this trapping strategy reduced the number of beneficial insects caught by 46% and the electricity consumption by 50% compared to the traditional strategy. Thus this strategy is more beneficial-friendly than the traditional trapping strategy for controlling pests., Gang Ma, Chun-Sen Ma., and Obsahuje seznam literatury
The parasitoid wasp Dinocampus coccinellae has been reported to parasitise adult, pupal and larval coccinellids. Field samples of larvae and pupae of Coccinella septempunctata, collected over 13 years in Britain, have failed to reveal any infected pre-imaginal individuals. The parasitisation rates of D. coccinellae into pre-imaginal and adult C. septempunctata were assessed in both choice and no-choice tests. Observations and test results revealed that British D. coccinellae have a strong preference to oviposit in adult coccinellids rather than larvae or pupae. This preference decreases as wasps age if denied oviposition opportunities.
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 abundance and distribution of coccinellids in non-crop habitats was studied using removal sampling and visual observation. Coccinellids were most frequently found on grassland habitats. Coccinellid abundance appeared to be most strongly correlated with the percentage ground cover of thistle, grasses and nettles. The most commonly collected coccinellids were Coccinella septempunctata and Adalia bipunctata comprising 60% and 35% of the catches respectively. Most coccinellids were found on Rubus spp. with nettles (Urtica dioica) and grasses being the next most favoured plant species. Adalia bipunctata was the most commonly found coccinellid species on nettles and birch (Betula spp.) whereas C. septempunctata was the most commonly found species on grasses, Rubus spp. and oak (Quercus spp.). These results are discussed in light of current thinking on the importance of "island" habitats as pali of an integrated pest management programme.