Seasonality of insect succession on exposed rabbit carrion in Guangzhou, China

Abstract  Succession patterns for insect fauna, spanning four seasons, on rabbit carcasses were studied in Guangzhou China from 2006 to 2008. A total of 49 taxa belonging to three orders and 15 families were collected and identified. Four decomposition stages were recognized: fresh, bloated, decay and dry stage. Taxa diversity was higher in bloated and decay stages than fresh and dry stages. Internal and ambient temperatures were measured. Maximum internal temperature arrived earlier in warmer seasons. The sequence of insect succession in this study follows the same general patterns: the Diptera peaked initially, and the Coleoptera peaked later. Chrysomya megacephala was the dominant species in four seasons. Its time point of different development stages on carrion could be the most important indicators for PMI (postmortem interval) estimation in Guangzhou. Yearly and seasonal differences in activities of insects were compared. Alpha diversity indices were calculated. There were no significant differences in Shannon-Wiener index, evenness ( J ) and dominance ( C ) between seasons and years. From the Jaccard similarity index, the highest similarity was between winter and spring, while the lowest was between summer and winter. Some species occurring exclusively in one season may be important to characterize different seasons. A list of the insect taxa associated with above-ground rabbit carrion during the four seasons was compiled, which can be used for estimating time since death in similar bio-climate areas.     

Consistency of seasonal patterns of insect succession on pig cadavers at Yeongdo Island in Busan,Korea

Cadaver insects cause dead bodies to break down in ecological processes. Still, the knowledge has been accumulated slowly about the structure and role of the insect assemblages attending to death scenes. This study analysed the successional patterns of insects on pig cadavers in the spring, summer, and autumn from 2016 to 2019 at Yeongdo Island, Busan, South Korea. A sum of 71 insect species belonging to four orders and 21 families were sampled. Predominant insects were largely Diptera and Coleoptera. The majority of the flies were the calliphorids as Chrysomya pinguis (Walker) and Lucilia porphyrina (Walker). The most common beetles were Creophilus maxillosus (L.), Omosita japonica (Reitter), and Staphylinidae sp. regardless of seasons. Occurrence matrices were made from the successional patterns of insect species during 42 sampling intervals in the spring, 38 sampling intervals in the summer, and 26 sampling intervals in the autumn. Permutation analyses of the occurrence matrices showed that the patterns of succession were similar between spring 2016 and 2017 (P = 0.019), between summer 2016 and 2017 (P = 0.003), and between autumn 2016 and 2019 (P = 0.002). The result shows that there are clear patterns in succession between seasons, and provides the reference data to presume the death time, at least in the southeast part of South Korea.     

珠江三角洲猪尸体上昆虫群落的演替及其对法医学中死亡时间推断的指示意义

为了解决刑事案件中死者死亡时间推断的难题,不同季节野外环境用18头猪尸体做模拟材料观察和筛选对推断死亡时间高度准确的昆虫指标。结果表明,幼虫开始出现时间、幼虫开始爬离时间、大部分幼虫爬离尸体的时间、开始化蛹的时间、大部分幼虫化蛹的时间、开始羽化的时间、羽化结束的时间等若干昆虫指标比较敏感且稳定可用作死亡时间的精确推断。在珠江三角洲春季、夏季及秋季尸体腐败很快,分别在259±23,202±18,277±20 h进入白骨化期,而冬季则时间较长,约经过1 297±63 h才进入白骨化期。大约有47种嗜尸性昆虫在尸体生态环境出现,大多数种类全年可见,尸体上的昆虫群落的优势种为大头金蝇Chrysomya megacephala、绯颜裸金蝇Achoetandrus rufifacies及厚环黑蝇Hydrotaea (Ophyra) spinigera。蝇类昆虫在尸体上只能大规模繁殖一代尸体即白骨化。根据以上结果可确定一些可用于死亡时间推断的关键时间点。     

Insects Associated with Pig Carrion in Two Environments of the Brazilian Savanna

Studies of carrion fauna have increased in Brazil and have contributed to the knowledge of this fauna in the national territory. Brazil has continental dimensions and presents various biomes in its territorial area. Most of the carrion fauna have seldom been studied, and this is especially true for the Savanna or “Cerrado.” The present research examined the fauna visiting carrion in two environments and two seasons in a rural area situated in a region of Cerrado in southeastern Brazil. The two environments studied were a pasture and a fragment of semi-deciduous forest. Samples were collected during the dry and humid seasons of the year. The study identified the diversity and relative abundance of species attracted to pig carcasses (Sus scrofa L.) exposed in each environment and season. Eight pig carcasses (10 ± 1 kg) were placed in traps, and adult insects attracted to the traps were collected during the decay of the carcasses. A total of 92,489 insects were collected during the experiments. The Diptera was the most frequent order (92.2%) represented by 27 families and at least 124 species. This was followed by Coleoptera (4.4%) represented by 14 families and at least 65 species. Sarcophagidae had the greatest diversity of species, followed by Muscidae and Calliphoridae. Several species were collected only during a specific period of the year or in a single environment. The results are important from an ecological point of view and for Medico-Legal Forensic Entomology.     

Influence of habitat modification on the intestinal helminth community ecology of cottontail rabbit populations

The influence of five brush management treatments using the herbicides tebuthiuron and triclopyr, with or without prescribed burning, on the intestinal helminth community of cottontail rabbits (Sylvilagus floridanus) was studied in 1987 on the Cross Timbers Experimental Range in Payne County, Oklahoma (USA). Six helminth species were found (Dermatoxys veligera, Trichostrongylus calcaratus, Passalurus nonanulatus, Wellcomia longejector, Taenia pisiformis cystercercus, and Mosgovoyia pectinata americana) in 102 rabbits (88 adult and 14 juveniles) collected over two seasons (winter and summer). Prevalence of M. pectinata americana in cottontail rabbits was significantly greater in untreated control pastures than herbicide treated pastures in winter, while prevalence of T. pisiformis was significantly greater in burned than unburned pastures. Abundances of helminth species in the intestinal tract of cottontail rabbits were unaffected by brush treatments. Mosgovoyia pectinata americana abundance demonstrated a highly significant increase from winter to summer; conversely, abundance of all oxyurid pinworms combined (D. veligera, P. nonanulatus, W. longejector) was significantly higher in winter than summer. Helminth community dynamics were significantly influenced by season, but were unaffected by brush treatments. Habitat modification could have influenced cestode transmission by altering the ecology of invertebrate and vertebrate hosts.     

Winter ecology of Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis>) and brown trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) in a subarctic lake,Norway

We studied habitat choice, diet, food consumption and somatic growth of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) during the ice-covered winter period of a subarctic lake in northern Norway. Both Arctic charr and brown trout predominantly used the littoral zone during winter time. Despite very cold winter conditions (water temperature <1°C) and poor light conditions, both fish species fed continuously during the ice-covered period, although at a much lower rate than during the summer season. No somatic growth could be detected during the ice-covered winter period and the condition factor of both species significantly declined, suggesting that the winter feeding rates were similar to or below the maintenance requirements. Also, the species richness and diversity of ingested prey largely decreased from summer to winter for both fish species. The winter diet of Arctic charr <20 cm was dominated by benthic insect larvae, chironomids in particular, and Gammarus lacustris, but zooplankton was also important in December. G. lacustris was the dominant prey of charr >20 cm. The winter diet of brown trout <20 cm was dominated by insect larvae, whereas large-sized trout mainly was piscivorous, feeding on juvenile Arctic charr. Piscivorous feeding behaviour of trout was in contrast rarely seen during the summer months when their encounter with potential fish prey was rare as the small-sized charr mainly inhabited the profundal. The study demonstrated large differences in the ecology and interactions of Arctic charr and brown trout between the winter and summer seasons.     

昆虫分布南界的形成原因及影响因素

生物都有一定的适生区,低温导致其分布北界的形成是不争的事实,然而一些种类还存在分布上的南界。昆虫的生长发育与环境的关系非常密切,研究其分布南界的形成原因对预测昆虫种群的扩散和暴发具有重要意义。从环境、寄主和人类活动等方面总结了北半球昆虫分布南界形成的机制及影响因素。低纬度地区夏季高温引起昆虫死亡率上升、生殖率下降、昆虫体内共生菌解体和冬季低温过高导致昆虫滞育节律被破坏等是昆虫分布南界形成的主要原因。此外,寄主的分布和人类活动也对昆虫分布南界存在一定影响。气候变暖对不同种类昆虫的分布南界影响不同,大部分昆虫的分布范围会扩大,但一些受环境限制的昆虫分布南界往往北移。建议今后对全球气候变暖背景下昆虫分布南界的变化、检疫性害虫在其原产地和入侵地分布南界的差异及其原因进行研究,以期为分析昆虫分布的变化提供依据,也为害虫防治提供新的可能途径。     

Seasonal variation in the diet of South African Galagos

The feeding behavior and diet of two species of bushbaby, Galago senegalensisand Galago crassicaudatus,in South Africa were examined in relation to seasonal changes in climate. The populations studied were allopatric, but both fed predominantly on Acaciagum and invertebrates. Data on their diet were collected by direct observation of a radiocollared female of each species and by analysis of fecal samples. Differences in diet were found between the species within seasons and within species between the seasons. Both spent more time gum-feeding in winter than in summer. Prey size and type differed between the species in summer but converged in winter. The quantity of insects taken was fairly similar between seasons for G. senegalensisbut dropped considerably for G. crassicaudatusin winter. These observations are interpreted in terms of interspecific differences in feeding strategies, which are considered to be a function of the difference in body size of the two galago species.     

Association of immature mosquitoes and predatory insects in urban rain pools

Distribution among pools of six mosquito species and 23 predatory insect taxa were studied in temporary rain pools during the summer and fall season in Buenos Aires city. Both mosquito immatures and predators were disproportionally more abundant in pools with high flooded surface, depth, and duration. Mosquito immatures differed in their habitat use with respect to predators. Among mosquitoes, Ochlerotatus albifasciatus showed a different pattern when compared to the remaining culicids. More culicid and predatory insect taxa colonized the pools in those flooding events of longer duration. Ochlerotatus albifasciatus was the only mosquito species recorded during short duration events and the first one in colonizing the pools in long duration events. This species shared the pools mainly with early arriving adult predators. Three Culex species were recorded later and showed higher coexistence with most of the predatory taxa, mainly immatures of the genera Tropisternus, Rhantus, Liodessus, and Belostoma. A high heterogeneity between pools and seasons was observed. Multiple regression analyses showed a negative relationship of per capita change of Culex species with large-sized predators only in those cases where predators were collected in high abundances during the summer. No negative relationship of predators was detected in relation to per capita change and abundance of Ochlerotatus albifasciatus. Differences in duration of about two to three weeks seemed to significantly affect the abundance of both culicid and predatory taxa, suggesting that the urban pools analyzed in this study are on the extreme of suitable conditions for these aquatic insects.     

Aquatic insect emergence in two Great Lakes marshes

This study determined total number, biomass, taxa, and seasonal occurrence of adult aquatic insects emerging from four vegetation zones in one diked and one undiked freshwater coastal marsh on hypereutrophic lower Green Bay, Lake Michigan, USA during the summer of 1984. Floating box traps were placed in open water, sparse emergent, dense emergent, and wet meadow vegetation zones in each marsh. Insects were collected during 20 24-hour periods, each four days apart, from June 11 to August 26. Two-way ANOVA was used to test differences in number and biomass of insects between marshes and among vegetation zones. Polynomial regression was used to evaluate seasonal emergence patterns. More insects, insect biomass, and insect taxa were found in the diked marsh, especially during the first half of the sampling period. Damselflies were much more abundant in the diked marsh. Most insects and insect biomass were found in the sparse emergent vegetation zone of both marshes. The emerging insect community in the diked marsh appears enhanced by its separation from the hypereutrophic and turbid waters of lower Green Bay.     

Comparison of the Decomposition VOC Profile during Winter and Summer in a Moist,Mid-Latitude (Cfb) Climate

The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC×GC-TOFMS were demonstrated for detecting and identifying trace levels of VOCs, particularly ethers, which are rarely reported as decomposition VOCs.     

Flaxseed oil modulates testicular biometrics,hormone, libido,antioxidant and semen profiles in endangered Teressa goat of Andaman and Nicobar Islands

Teressa goat is a unique goat breed in Andaman and Nicobar Islands (ANI) of India. Effects of Flaxseed oil (FSO) supplementation in body weight (BW), scrotal circumference (SC), testicular volume (TV) and testicular weight (TW), endocrinological profiles, sex behavioural profiles (SBPs), oxidative stress markers and semen production and its quality profiles in rainy and dry summer season were studied in Teressa goat. Male goats (n = 12) of 3–4 years old were equally divided into control and treated groups. Treated animals received 25 mL FSO per day. Oral drenching of FSO was done in the morning before feeding the concentrate ration. Body weight, scrotal circumference, TV and TW were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Blood follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), cortisol and prolactin, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Libido score (LS), mating ability score (MAS) and sex behavioural score (SBS) were estimated at time of semen collection in bucks of FSO treated and untreated during rainy and dry summer seasons. Semen samples (n = 100; 50 semen samples from each season; each 25 semen samples from control and treatment groups per season) were collected and analysed for semen quality profiles. One-way ANOVA (control rainy, control dry, treated rainy and treated dry) revealed that BW, SC, TV and TW, FSH, LH, testosterone, TSH, T3 and T4 were higher (P < 0.05) and cortisol and prolactin were lower (P < 0.05) in FSO treated bucks of rainy season followed by untreated bucks of rainy season, FSO treated bucks of dry summer season and were lower (P < 0.05) in untreated bucks of dry summer season. Similarly, TAC, CAT, SOD and GSH, LS, MAS and SBS, and volume, pH, sperm concentration, mass activity, total motility (TM), viability, acrosomal integrity (AcI), plasma membrane integrity (PMI) and nuclear integrity (NI) were higher (P < 0.05) and MDA and TSA were lower (P < 0.05) in FSO treated bucks of rainy season followed by FSO treated bucks of dry summer season, untreated bucks of rainy season and were lower (P < 0.05) in untreated bucks of dry summer season. The results of the present study indicated that the breeding bucks suffered physiological stress (higher cortisol), oxidative stress (higher MDA and deficiency of antioxidants), hormonal imbalance (higher prolactin and cortisol and deficiency of gonadotropins, gonadal hormone and thyroid hormones) and infertility due to poor libido and poor semen production and its quality profiles during dry summer season. Thus, dry summer was more stressful season compared to rainy season for the goat bucks. FSO supplementation mitigated these stresses and improved the scrotal and testicular biometrics, libido, antioxidants, hormones and semen quality profiles in Teressa goat bucks. The current study concluded that FSO effectively improved the hormones, libido, antioxidant profiles, and scrotal and testicular biometrics with cascading beneficial effects on semen quality profiles in Teressa goat bucks under humid tropical island ecosystem of Andaman and Nicobar Islands.     

The predators of insects

Abstract. 1. Insect–insectivore trophic relations were reviewed using presence–absence data from sixty-one invertebrate-dominated food webs and fifteen food webs from Briand's (1983) original forty web collection. From counts of prey links in higher taxa (orders, classes, phyla), six phyla and thirteen classes of non-insect insectivores and fourteen orders of insect predators and prey were found. 2. Detritus-based habitats (phytotelmata, felled logs, carcasses, dungpads) harboured fewer orders of insects, that interact with other insects, than webs from grazer-based (host plants, some galls) and mixed-based systems (aquatic webs). Consumer–resource networks of higher insect taxa in these webs shared several features found in some species-level biological networks: the trend was towards few pairs of strong asymmetrical links, several weak links and many null interactions. 3. From counts of insect predator–insect prey links, hymenopterans as terrestrial predators and parasitoids interacted with the most number of higher insect taxa. Hymenopterans were also linked as prey more often than other terrestrial insects. In freshwater habitats, plecopterans were linked as predators more often than other aquatic taxa, whereas dipterans were listed as prey more often than other insects. 4. Dipterans were linked in the diets of non-insect insectivores from seven of eight common taxonomic classes. Arachnids were identified as insect predators by food web researchers in the largest number of webs, followed by passerine birds and cyprinodont fishes. From analysis of prey links at the ordinal level, predaceous insects were less polyphagous than other predators (other ectotherms and endotherms). 5. Analysis of chain lengths, as expected, showed that insect prey occupied mostly lowermost trophic levels, non-insect insectivores were found mostly at uppermost trophic levels, and predaceous insects were found mostly at intermediate trophic levels across most habitats. 6. This analysis offers evidence that insects are not just occupying intermediate trophic levels in some communities. Indeed, some taxa feed at the upper ends of long food chains, for example eupelmids in galls, staphylinids in carcasses, and perlid plecopterans in streams.     

Evaluation of three varieties ofOpuntia ficus-indica (L.) Miller as hosts of the Cochineal insectDactylopius coccus costa (Homoptera: Dactylopiidae) in a semiarid area of northeastern Mexico

Three varieties of prickly pearOpuntia ficus- indica (Villanueva, Copena, and Jalpa varieties) were evaluated in their capacity to be host of the cochineal insect (Dactylopius coccus Costa) in two localities of northeastern Mexico. The experiment was carried out for two seasons, winter and summer, in 1998. Variables under evaluation were: fresh weight of grana, dry weight of grana, and number of insects. The Villanueva variety showed the highest production for the three variables and there were no differences between the other two varieties. Iturbide locality was superior to Linares for the three variables. Higher production (both dry and fresh weight of grana) was obtained during winter and there were no differences between seasons for number of insects. Figures obtained for the Villanueva variety are slightly higher than those reported in literature for the most productive cochineal areas in Mexico.     

Delaying insect access alters community composition on small carrion: a quantitative approach

We present a study of interactions in the highly competitive insect communities inhabiting the carrion of small mammals. Via manipulation in a fully quantitative design, we delayed community development by excluding insect colonization in mouse and rat carcasses for 3 days, to study the role of early competitively dominant colonizers [burying beetles (Nicrophorus spp.; Coleoptera: Silphidae) and blowfly larvae (Diptera: Calliphoridae)] in the course of heterotrophic succession on small cadavers. Earlier studies demonstrated that in the case of large mammalian carrion, exclusion of insects’ access to the carcass in the early stages of decomposition altered the successional trajectory and species assemblages. However, the effect of such manipulation in easy monopolizable small vertebrate carrion remained unknown. Our results demonstrate that delaying insect access to carrion significantly lowered blowfly larvae abundances, while it simultaneously had no effect on colonization and carrion burial by burying beetles. Higher abundances of blowfly larvae seem to deter necrophagous beetles, whereas they are not harmful to the larvae of flesh flies, at least in larger rat carcasses. Predatory beetle species preferred the lower abundances of blowfly larvae, presumably due to better accessibility of their prey. Our results therefore suggest that in the course of the entire season, larvae of blowflies are the dominant competitors in small carcasses, and significantly affect the assembly of other insect groups, whereas burying beetles may exhibit a more temporal pattern of dominance.     

Seasonal variation of the capture and field distribution of sterile Anastrepha ludens in Tamaulipas,Mexico

Anastrepha ludens (Loew) (Diptera: Tephritidae) is one of the most important citrus pest in Mexico. The sterile insect technique (SIT) is used against pest populations of fruit flies for suppression, eradication, containment and prevention to reduce damages in fruit‐growing areas. In this study, we analyzed the seasonal variation of captures and field distribution of sterile A. ludens released in different seasons of the year in north‐eastern Mexico. Chilled releases were conducted by air at constant densities per ha on a citrus area for a period of 32 weeks that included the coldest and warmest seasons that is winter, spring and summer. Multilure traps baited with torula yeast pellets were used to capture sterile flies. Fly capture data were compared over the three seasons and correlated with climate. The lowest number of captures of the sterile insect occurred in the summer and the highest in winter and spring. High and low temperatures were negatively correlated with fly captures. Field distribution was also negatively correlated with high temperatures in summer, but no relationships were observed in winter and spring. No relationships were observed between rainfall with capture and field distribution of sterile flies. These results indicate that summer is a season involving agro‐ecological and environmental constraints for the capture and field distribution of sterile flies. This study may be useful for enhancing release strategies and optimizing economic resources in north‐eastern Mexico. Further research on the behaviour of sterile flies under stressful environments is suggested.     

A checklist of arthropods associated with pig carrion and human corpses in southeastern brazil

Necrophagous insects, mainly Diptera and Coleoptera, are attracted to specific stages of carcass decomposition, in a process of faunistic succession. They are very important in estimating the postmortem interval, the time interval between the death and the discovery of the body. In studies done with pig carcasses exposed to natural conditions in an urban forest (Santa Genebra Reservation), located in Campinas, State of S?o Paulo, southeastern Brazil, 4 out of 36 families of insects collected - Calliphoridae, Sarcophagidae, Muscidae (Diptera) and Dermestidae (Coleoptera) - were considered of forensic importance, because several species were collected in large numbers both visiting and breeding in pig carcasses. Several species were also observed and collected on human corpses at the Institute of Legal Medicine. The species belonged to 17 different families, 6 being of forensic importance because they were reared from human corpses or pig carcasses: Calliphoridae, Sarcophagidae, Muscidae, Piophilidae (Diptera), Dermestidae, Silphidae and Cleridae (Coleoptera). The most important species were: Diptera - Chrysomya albiceps, Chrysomya putoria, Hemilucilia segmentaria, Hemilucilia semidiaphana (Calliphoridae), Pattonella intermutans (Sarcophagidae), Ophyra chalcogaster (Muscidae), Piophila casei (Piophilidae); Coleoptera - Dermestes maculatus (Dermestidae), Oxyletrum disciolle (Silphidae) and Necrobia rufipes (Cleridae).     

Effect of ante- and postmortem hide clipping on the microbiological quality and safety and ultimate pH value of beef carcasses in an EC-approved abattoir

Aims:  Effect of ante- and postmortem hide clipping on the microbiological quality of beef carcasses. Methods and Results:  Bovine carcasses (362) were tested for indicator micro-organisms and the presence of pathogens. Prior to slaughter, hide cleanliness of each animal was categorized on a scale of 1–5 (clean to dirty). Lowest mean aerobic colony counts (ACC) (log₁₀ 3·0 CFU cm⁻²) came from carcasses where clipping had been performed in lairage, antemortem. ACC from animals clipped online (log₁₀ 3·2 CFU cm⁻²) were significantly higher (P < 0·05) than those clipped in lairage, but comparable to those carcasses from Category 1 and 2 animals. There were no significant differences in the detection of pathogens from any of the carcass groups. Ultimate pH values for carcasses from Category 3 and 4 animals showed clipping animals in lairage, as opposed to online, resulted in a small, but significant increase (P < 0·05) in pH value (mean pH 5·66 and 5·59, respectively). Conclusions:  Hide clipping does not adversely affect microbiological quality of carcasses, although higher ultimate pH values indicate increases in antemortem stress. Significance and Impact of the Study:  Hide clipping carcasses both ante- and postmortem appears to be an effective intervention to minimize transfer of hide microflora to carcasses during slaughtering operations. Online clipping offers advantages for animal welfare and improves safety for operatives.     

The adult body size variation of Dryas iulia (Lepidoptera,Nymphalidae, Heliconiinae) in different populations is more influenced by temperature variation than by host‐plant availability during the seasons

The body size of insects is affected by environmental conditions during development and can present considerable intraspecific variations, which can be seen as an ultimate consequence/adaptation to environmental conditions. This paper evaluated whether the body size of the butterfly Dryas iulia from subtropical populations was influenced by changing climate conditions and food source availability during the seasons. The likely reasons behind body size variation were also investigated. First, field data on body size variation, host‐plant availability and climate fluctuation throughout the seasons were recorded. Then, the effects of host‐plant species and temperature on body size were analyzed by controlled experiments. Field data revealed that body size and host‐plant availability varied significantly through the seasons. Populations had the smallest body size during the spring and the biggest size during summer, whereas host‐plant availability was lower during winter and higher during spring. The controlled experiments revealed that both temperature and host‐plant had significant effect on the plasticity of body size. Larvae subjected to winter temperature treatment led to smaller butterflies when compared to immatures reared under summer temperature treatment, and larvae fed with Passiflora misera produced bigger adults when compared to larvae reared on Passiflora suberosa. The combination of data gathered in the field and in the laboratory suggests that seasonal body size variation in D. iulia is related mainly to differences in the temperatures to which larvae are subjected during development, while host‐plant shifts caused by differential availability of food through the seasons had slightly effects on the variation observed.     

高原鼠兔肠道微生物中丰富及稀有类群的季节性特征

气候及食物是驱动植食性小哺乳动物肠道菌群产生季节性变化的重要因素。然而,此类研究很少涉及肠道丰富及稀有微生物类群。本文以高原鼠兔（Ochotona curzoniae）为对象,通过16S rRNA基因测序和分析,探讨丰富及稀有肠道微生物类群的结构组成、多样性指数及功能在春、夏、秋、冬四季的变化特征。结果显示,丰富类群对菌群主要门和功能的季节性变异贡献大于稀有类群,稀有类群对菌群OTU和alpha多样性的变异贡献大于丰富类群。丰富类群和稀有类群的香农指数均在冬季显著高于其他季节;丰富类群的ACE指数在秋季显著低于其他季节,而稀有类群的ACE指数则在冬季显著高于春季和夏季。丰富类群中拟杆菌门（Bacteroidetes）的相对丰度在冬季和秋季显著高于春季和夏季,但在稀有类群中,夏季和秋季的相对丰度显著高于冬季和春季。丰富类群中氨基酸代谢通路的相对丰度在冬季显著高于春季和夏季,而在稀有类群中,其相对丰度在春季显著高于夏季和秋季。气温、降水量和植被中的营养物质与肠道菌群中丰富类群和稀有类群的变化均显著相关,环境变量对丰富类群和稀有类群变化的总解释率分别为18%（气温：3%;降水：4%;植被营养成分：10%;联合：1%）和9%（气温：1%;降水：2%;植被营养成分：5%;联合：1%）。以上结果表明肠道微生物中的丰富和稀有类群具有不同的分布模式和季节性特征,二者对整体菌群变异的贡献存在差异,环境因素更多地影响丰富类群,反映了肠道微生物不同类群对季节变化响应的非一致性。本研究增进了我们对哺乳动物肠道菌群季节性变化过程及环境适应性的认识。