Precocious egg development in the blowfly Calliphora vicina: implications for developmental studies and post-mortem interval estimation

The occurrence of precocious egg development in forensically important calliphorid species has previously been reported; however, the frequency of occurrence in both wild and captive colonies, and the consequent effects on developmental studies and post-mortem interval (PMI) estimates, are largely unknown. A PMI estimate based on samples developed from precocious eggs could be extended by the entire period of embryogenesis, which at 22 °C would result in a significant error of around 24 h. This study examined the occurrence of precocious egg development in Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) wild-caught and captive-bred adults by investigating the presence of larvae in the adult female genital chamber and by monitoring hatching times of entire batches of eggs throughout embryogenesis, respectively. A total of 8.82% of gravid wild-caught females contained a larva in the genital tract (i.e. a precocious egg). This indicates that all specimens collected should be considered potentially precocious for the purpose of PMI estimation. Less than 2.55% of a batch of eggs laid by captive females were precocious; protocols for minimizing the effect of precocious eggs on developmental studies are suggested.     

Hybrid carrot seed crop pollination by the fly Calliphora vicina (Diptera: Calliphoridae)

Many insect species can contribute to crop pollination; however, most growers remain highly dependent on the managed honey bee (Apis mellifera L.) for this service. The European Blue Blow Fly Calliphora vicina Robineau‐Desvoidy, 1830 is one species with potential use as a pollinator. It occurs worldwide and is easy to rear. Caged trials conducted within a hybrid carrot (Daucus carota L.) seed crop found C. vicina to be an effective pollinator. Seed yield (number and weight) from field‐grown carrot plants caged with C. vicina, but excluding all other large flower visitors (body width > 3 mm), was similar to seed yield from uncaged plants in the presence of honey bees (Apis mellifera L.) and other insects. In contrast, caged plants without C. vicina produced 10‐fold less seed. Under open field conditions, C. vicina spent an average of 71.0 s per umbel compared to 54.4 s for honey bees; however, under caged conditions, C. vicina spent more time on average per umbel (128.9 s). Counts of C. vicina and honey bees on umbels outside of cages and C. vicina inside cages found that honey bees were most abundant on days with maximum temperature > 25°C, while C. vicina was more abundant on cooler days around 20°C. C. vicina may therefore be a useful pollinator of crops grown in isolation cages for plant breeding purposes as well as in open fields when climatic conditions are less favourable for optimal honey bee activity.     

Assessment of the Biological Control Impact of Seed Predators on the Invasive Shrub Acacia nilotica (Prickly Acacia) in Australia

An impact assessment study was undertaken to determine seed predation rates by two bruchid beetles, Bruchidus sahlbergi Schilsky and Caryedon serratus Olivier, on the invasive shrub Acacia nilotica (L.) Willd. ex Del. The former bruchid was released as a biological control agent for A. nilotica, whereas the latter is naturalized in Australia. We attempted to determine the dynamics and magnitude of bruchid predation, following a number of differing reports of their effectiveness. To investigate the importance of seed availability on bruchid numbers, we compared seed death in high- and low-seed-density habitats, both before and after pods had dropped from tree branches. Bruchid predation was initially low (<2%) in pods on tree branches in both habitats, but increased abruptly to 12% in riparian and 32% in nonriparian exclosures by the third collection date. Bruchid numbers then crashed to below 2% in both habitats, when pods dropped to the ground. B. sahlbergi predation later increased markedly (up to 65%) again at high-pod-density sites. No further increase in predation took place beyond this level. Seed predation by C. serratus was found to be minimal (<5% of seeds infested) throughout the monitoring period. We suggest that seed predation by the bruchids, prior to pod drop and removal by cattle, is insufficient to cause major impacts on A. nilotica populations. Bruchid seed damage is likely to be significant only in situations with low cattle numbers, where cattle cannot remove the majority of fallen seed pods or where cattle are excluded. Exclusion of cattle from some areas within A. nilotica-invaded landscapes to potentially increase bruchid effectiveness is proposed. The demographic impact of optimal A. nilotica seed losses is discussed.     

CREB在拟黑多刺蚁不同品级脑部mRNA水平的定位

为探讨CREB在拟黑多刺蚁(Polyrhachis vicina)不同品级脑部mRNA水平的表达,采用地高辛标记法原位杂交技术对拟黑多刺蚁工蚁、雌蚁、雄蚁3个品级脑部CREB mRNA的表达进行了定位研究。结果显示,CREB mRNA在拟黑多刺蚁不同品级脑部均有广泛表达。阳性反应主要分布在蕈形体冠部的Kenyon细胞、视叶和嗅叶等部位。在3个不同品级蚂蚁的脑部中,工蚁的嗅球和蕈形体内有较明显的CREB mRNA阳性反应,雄蚁的视叶具有较强的阳性反应,与工蚁和雄蚁相比,雌蚁脑部各个部位的阳性表达都较弱。推断CREB可能在视觉和嗅觉信息的获取与整合中起着重要作用,且与不同品级蚂蚁的行为相关。     

Lifetime reproductive output of Calliphora vicina and Lucilia sericata in outdoor caged and field populations; flight vs. egg production?

Females of the blowflies Calliphora vicina (Robineau-Desvoidy) and Lucilia sericata (Meigen) (Diptera: Calliphoridae) maintained in sheltered outdoor cages and supplied with excess food, oviposited later than would have been expected from the temperature-sum. The survival rates of the caged flies was high and the isolation of flies from predation, extreme temperatures and food shortages is likely to have contributed to this. Despite good survival rates, subsequent egg production over the greater part of the adult life span was reduced to approximately 24% for C. vicina and approximately 55% for L. sericata, of the potential expected from the published temperature-sums required for the maturation of successive egg batches. The data suggest that under field-cage conditions there is a considerable variation in egg development between individuals of the same age and that this variation should not be overlooked, since it may have significant implications in ecological and forensic investigations; however, the cause of this variability remains unclear. While lower than expected, the reproductive outputs recorded in the cages were nevertheless considerably greater than those that have been estimated for blowflies in the field and illustrate the potential for population increase in these species under favourable conditions. The possibility of a greater energy investment in flight activity relative to reproductive output in C. vicina compared to L. sericata is proposed.     

舍蝇的寄生真菌——堪萨虫霉

本文报道了在福建南平地区引起舍蝇(Musca domestica vicina Macquart)流行病的堪萨虫霉(Entomophthora kansana Hutchison)的鉴定工作。该菌子生孢子梨形,大小29.2—49.5×23.1—42.9/μm,平均39.6×31.4μm.次生分生孢子近球形,基部平截,平均大小23.8×21.7μm,虫菌体球形或近球形。假根,囊状体及休眼孢子缺乏。     

Maternal temperature has different effects on the photoperiodic response and duration of larval diapause in blow fly ( Calliphora vicina ) strains collected at two latitudes

Abstract .The blow fly Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) has a wide distribution across northern and temperate Europe. It has a facultative, maternally-induced larval diapause in response to short days. The photoperiodic response, measured at 15 and 20°C, of two populations was compared. A southern population (originating at 51° N) was sensitive to temperature at all daylengths; the incidence of diapause was greatly reduced at 20°C compared with 15°C. The photoperiodic response of a northern population (from 65° N) was sensitive to temperature only in long days; in short days (< 14 h of light) the response of this strain was identical at each temperature.
Variation in parental photoperiod and temperature were found to affect the duration of larval diapause, indicating a role for maternal effects in diapause intensity as well as incidence. However, the between-strain variation was greater than that within strains, indicating qualitative differences in diapause response. These differences may arise from the ecological conditions at the points of origin of the two strains. The northern strain from the harsher climate has a more intense diapause that follows a relatively temperature-insensitive photoperiodic response. In contrast, the southern strain has a shallow diapause and its photoperiodic response may be overridden by the experience of concurrent high temperature.     

罗非鱼脑垂体结构研究：Ⅰ.腺垂体前叶的超微结构

本文研究尼罗非鲫Oreochromis nilotica腺垂体前叶的超微结构。前叶主要由促肾上腺皮质激素分泌细胞(ACTH)、催乳激素分泌细胞(PRL)和一种非分泌类型的星状细胞(SC)所构成。对脑垂体结构的周年观察,表明在产卵期间ACTH细胞和PRL细胞均高度活跃,ACTH的分泌可能促进排卵活动,而PRL的分泌活动则受温度变化的影响。腺垂体前叶只接受B型神经分泌纤维的直接支配,星状细胞和Ⅱ型脑垂体细胞则参与腺细胞分泌颗粒的释放和运输等活动。本文并讨论了腺细胞的分泌颗粒通过胞吐和扩散两种方式释放等特点。     

Effect of long-term in vitro shoot culture on somatic embryogenesis of quince leaves treated with different light qualities

Summary The effect of long-term in vitro shoot culture on somatic embryogenesis in quince BA 29 was investigated. Three experiments were performed on leaves explanted at about 8-mo. intervals from the same culture stock and maintained under different light qualities. Embryo production was assessed either in terms of percentage of embryogenic leaves or number of embryos per leaf. By appropriate data processing both these responses were linearly related to photoequilibrium in each experiment. Statistical comparisons among the three experiments showed significant differences both in mean (computed over light qualities) and line slope values. In particular, with increasing shoot culture age, both percentage of embryogenic leaves and number of embryos per leaf progressively increased, while mean slope values decreased. The increase in mean values suggests a positive effect on somatic embryogenesis due to possible tissue rejuvenation when mother cultures were cultivated in vitro for longer periods. Slope decrease over time indicated the interactions between age of the in vitro culture and photoequilibrium. Thus, embryo production at different culture ages was consistently found to be highest at high photoequilibrium values; in contrast, if a low level of phytochrome was activated, embryogenesis in the youngest cultures was low or absent, but increased with the progressive tissue rejuvenation arising from long-term in vitro culture.     

Morphology of the first instar of Calliphora vicina, Phormia regina and Lucilia illustris (Diptera, Calliphoridae)

Scanning electron microscopy documentation of first instar Calliphora vicina Robineau-Desvoidy, Phormia regina (Meigen) and Lucilia illustris (Meigen) (Diptera: Calliphoridae) is presented for the first time, and the following morphological structures are documented: pseudocephalon; antenna; maxillary palpus; facial mask; labial lobe; thoracic and abdominal spinulation; spiracular field; posterior spiracles, and anal pad. Light microscopy documentation and illustrations are provided for the cephaloskeleton in lateral and ventral views. New diagnostic features are revealed in the configuration of the facial mask, cephaloskeleton and posterior spiracles. The first instar morphology of C. vicina, Ph. regina and L. illustris is discussed in the light of existing knowledge about early instars of blowflies.