不同饥饿程度的龟纹瓢虫成虫对烟蚜的捕食作用

试验研究了不同饥饿程度的龟纹瓢虫雌、雄成虫对烟蚜的捕食作用。结果表明,不同饥饿程度的龟纹瓢虫雌、雄成虫对烟蚜捕食的功能反应均为Ｈｏｌｌｉｎｇ Ⅱ型,雌成虫的瞬间攻击率ａ大于雄成虫;不同饥饿程度的龟纹瓢虫雌、雄成虫在２４ｈ内对烟蚜的捕食量差异不显著;雌成虫捕食量大于雄成虫;饥饿时间愈长,烟蚜密度愈大,雌雄成虫间捕食量差异愈显著;未饥饿的龟纹瓢虫雌、雄成虫在２４ｈ内对烟蚜的捕食行为集中在６：００～１８     

两种豆科作物田捕食性瓢虫群落研究

利用生物多样性研究方法, 对通辽市科尔沁区两种豆科作物田开花期捕食性瓢虫群落进行研究。结果表明: 两种捕食性瓢虫群落的物种组成和发生个体数量上存在差异, 具体为大豆田分布捕食性瓢虫8属10种, 以异色瓢虫Harmonia axyridis (Pallas)数量最多(122头); 苜蓿田分布5属8种, 以多异瓢虫Hippodamia variegata (Goeze)数量最多(68头)。两个捕食性瓢虫群落相似性较高, 差异性较大的捕食性瓢虫物种其个体数量均明显多于其它物种。色斑型研究显示异色瓢虫具27种变型, 多异瓢虫有8种, 龟纹瓢虫Propylea japonica (Thunberg) 有6种变型; 且大豆田捕食性瓢虫色斑变型(共35种)明显多于苜蓿田(共16种)。     

龟纹瓢虫对豆蚜的捕食功能反应及寻找效应研究

龟纹瓢虫雌虫和雄虫对豆蚜的功能反应符台Holling Ⅱ型模型,其模型为：Na=0．9233N／(1 0．0171N)(雌虫)和Na=0．8641N／(1 0．0164N)(雄虫),瓢虫捕食豆蚜的数量随豆蚜密度增加而增加．但寻找效应随豆蚜密度增加而降低。日最大捕食量和最佳寻找密度分别为37.42(雌)、34．11头(雄)和17．25（雌)、15．8头(雄)。龟纹瓢虫寻找效应随自身密度的增加而降低,其数学模型为：E=0．3032·P^-15634(雌)和E=0．3048·P^-1.1697(雄)。干扰反应的教学模型为：E=0．8104·P^-2.1721(雌),E=0．7125·P^-2.2660,E=0．5963·P^-2.1751(雌雄混台种群)。     

人工饲料对龟纹瓢虫生长和繁殖的影响

龟纹瓢虫Propylaea japonica(Thunberg)能捕食多种农业害虫,并且具有食量大、产卵多、适应性强、年发生代数多等特点,是我国农业生产中一种重要的捕食性天敌昆虫。对龟纹瓢虫人工饲料的研究则是实现其规模化饲养的关键。作者研究不同饲料对龟纹瓢虫生长和繁殖的影响,结果表明:添加橄榄油后幼虫发育历期明显增长,添加0.3%的橄榄油能显著提高幼虫的成活率;在成虫体重增长上,雌雄虫均表现为在刚羽化后几天内体重增长显著,随后增长变缓;并且添加蔗糖能显著提高雌虫的体重增长率而对雄虫作用不显著;对雌虫繁殖性能的研究发现,蚜虫喂养组有明显的持续时间较长的产卵高峰期,而人工饲料的产卵高峰期持续时间较短,并且出现时间较晚或分为2个高峰期;添加0.3%的橄榄油能显著缩短龟纹瓢虫的产卵前期,几乎达到蚜虫喂养组的水平;而添加蔗糖在一定程度也能缩短产卵前期,同时还能显著提高龟纹瓢虫的产卵量。     

龟纹瓢虫的行为学观察

通过以洋槐蚜Aphis robiniae Macchiati为食物对龟纹瓢虫Propylea japonica(Thunberg)进行室内饲养和观察,记述了龟纹瓢虫幼虫的孵化、蜕皮行为,成虫的羽化、捕食、交配、产卵行为,并对幼虫成虫的自残行为进行了初步观察。结果表明幼虫孵化、蜕皮,成虫羽化后均有取食自己蜕皮时产生的残皮的行为;龟纹瓢虫成虫捕食行为分为搜寻、捕捉、清洁、静止排泄4个步骤;交配一般由雄虫发起,雌虫背负成虫进行交配。龟纹瓢虫每产一粒卵平均耗时3.75秒,两粒卵之间产卵时间间隔约31.75秒,每次产卵量平均12枚;龟纹瓢虫存在自残行为,成虫在食物不足时会取食幼虫和虫卵,高龄幼虫在饥饿的状态下也取食低龄幼虫和卵,且同龄幼虫之间也会出现相互咬食的现象。     

二双斑唇瓢虫对矢尖蚧的捕食作用

研究了二双斑唇瓢虫（Chilocorus bijugus Mulsant)对矢尖蚧（Unaspis yanonensis Kuwana)的捕食作用,结果表明,瓢虫雌成虫对矢尖蚧各虫态的功能反应呈Holling II型,瓢虫对矢尖蚧的捕食效应随捕食者个体间干扰作用的增加而下降,捕食作用率（E）随着瓢虫数增加呈幂函数下降曲线,温度对瓢虫的捕食效应具有显著的影响,寻找效率（a)和处置时间（Th)与温度之间呈二次函数关系,猎物密度对瓢虫生殖力的影响呈Logistic曲线。     

异色瓢虫成虫对麦二叉蚜的捕食作用模型

通过异色瓢虫雌,雄成虫对麦二叉蚜捕食作用研究,得出：1．异色瓢虫雌、雄成虫对麦二叉蚜捕食作用的功能反应均是HollingⅡ型反应;2．异色瓢虫捕食麦二叉蚜时,同等数量的异色瓢虫雌雄混合的干扰作用大于同一性别成虫间的干扰作用;3．异色瓢虫雌、雄成虫均喜好捕食低龄若蚜．     

桃园捕食性节肢动物群落结构及动态研究

【目的】探讨桃园捕食性节肢动物群落特征、结构组成及动态规律,为桃园害虫防治提供依据。【方法】在西北农林科技大学实验站选择树龄5~6年的桃园为调查对象,系统调查园内节肢动物群落的种类和数量,测定群落的相对丰富度、多样性指数(H')、均匀度指数(E)及优势集中性指数(C)等指标,研究园内捕食性节肢动物群落的变化规律。【结果】桃园捕食性节肢动物群落的多样性指数和均匀度指数表现为高-低-高-低的趋势;群落优势度(B)与优势集中性指数呈现低-高-低趋势。食蚜蝇、蜘蛛、瓢虫、步甲和草蛉是桃园主要捕食性节肢动物亚群落。大灰食蚜蝇Metasyrphus corollae和黑带食蚜蝇Episyrphus balteata是食蚜蝇亚群落的优势种群,5月中旬至6月下旬是其发生高峰期;龟纹瓢虫Propylaea japonica是瓢虫亚群落的优势种群,5月中旬至7月下旬是其发生高峰期,随后数量维持在较低水平;龟纹瓢虫鼎斑变型和锚斑变型是桃园最常见的色斑变型,分别占49.6%和29%;蜘蛛亚群落主要包括皿蛛、蟹蛛和球蛛类群,5月上中旬、8月中下旬和10月中旬是其发生高峰期;步甲亚群落的发生高峰期为5月上旬至6月下旬,随后维持在较低的水平;中华草蛉Chrysoperla sinica为草蛉亚群落的优势种群,6月上旬至8月上旬是其发生高峰期。【结论】桃园捕食性节肢动物主要包括捕食性蜘蛛、食蚜蝇、捕食性瓢虫、步甲和草蛉5个亚群落,不同天敌亚群落的结构特征随着季节和气温的变化而相互演替,共同发挥控制害虫的作用。     

龟纹瓢虫成虫对3种害虫的捕食作用

为明确天敌昆虫龟纹瓢虫Propylea japonica对3种害虫莲缢管蚜Rhopalosiphum nymphaeae、紫薇长斑蚜Sarucallis kahawaluokalani和红带滑胸针蓟马Selenothrips rubrocinctus的捕食效应,分别在室内测定了龟纹瓢虫成虫对莲缢管蚜3~4龄若蚜、紫薇长斑蚜3~4龄若蚜和红带滑胸针蓟马2~3龄若虫的捕食作用。结果表明：龟纹瓢虫成虫对3种害虫的捕食效果可用Holling-Ⅱ模型进行拟合,对红带滑胸针蓟马2~3龄若虫的捕食能力最强,为192.14,对莲缢管蚜的捕食能力最弱,为91.12。龟纹瓢虫成虫对莲缢管蚜、紫薇长斑蚜和红带滑胸针蓟马的寻找效应呈线性相关,猎物密度越大寻找效应越低。龟纹瓢虫成虫对3种害虫的最佳搜寻密度分别为48.35、23.48和36.48头。由此可知,龟纹瓢虫对莲缢管蚜、紫薇长斑蚜和红带滑胸针蓟马具有一定的控害作用。     

龟纹瓢虫对扶桑绵粉蚧的捕食功能反应

为初步探究龟纹瓢虫Propylea japonica对入侵性害虫扶桑绵粉蚧Phenacoccus solenopsis Tinsley的生物防控能力,本实验在(T=26℃±2℃,R=80%±5%,L∶D=16∶8)条件下进行。将饥饿处理过的各个龄期的龟纹瓢虫分别与扶桑绵粉蚧不同密度的1龄若虫进行组合,在一定的时间内,测定各龄期的龟纹瓢虫对猎物进行的捕食量、捕食率。龟纹瓢虫1龄幼虫、2龄幼虫和成虫对扶桑绵粉蚧1龄若虫的功能反应属Holling-Ⅱ型反应,其捕食者的捕食率随猎物密度的增加而逐渐下降;龟纹瓢虫对猎物的处理时间Th随瓢虫龄期的增大而呈减小趋势。龟纹瓢虫3龄幼虫,4龄幼虫对扶桑绵粉蚧1龄若虫的功能反应属Holling-Ⅲ型反应,其捕食量随虫龄的增大而增加,发现率和最大捕食量也增大,平均处理时间减少。结果表明,龟纹瓢虫对扶桑绵粉蚧具有较强的控制潜能。     

Sexual dimorphism of body size and shell shape in European tortoises

Adult body size and shape were examined in almost 1400 individuals of the tortoises Testudo graeca , T. hermanni and T. marginata from Greece. The size at maturity was greater in females than in males in all three species. Maximum and mean adult sizes were also greater in females than in males in T. graeca and T. hermanni . Males grew to a larger size than females in T. marginata , and mean adult size was similar in the sexes in this species. Sexual dimorphism of shape (adjusted for size covariate) was shown in most of the characters examined, and the degree of this dimorphism differed significantly among the three species. Differences were related to their contrasting courtship behaviours: horizontal head movements and severe biting in T. marginata , vertical head bobs and carapace butting in T. graeca , and mounting and tail thrusting in T. hermanni . There was no difference in the frequency of observations of courtship or fighting among the three species, but courtship was about 10 times more common than combat in males. All species showed greatest courtship activity in autumn; copulation was rarely observed in T. hermanni (only 0.36% of courting males) and not seen in the other species in the field. Observations made throughout the activity season indicated that feeding was equally common in males and females in all three species. Differences in shape were more likely to be the result of sexual selection than of natural selection for fecundity. Detailed predictions are made for sexual dimorphism of other characters in these species.     

Does Female Personality Determine Mate Choice Through Sexual Cannibalism?

Animal personalities (e.g. consistent across‐context behavioural differences between individuals) can lead to differences in mate choice. However, evidence for this link remains limited. Pre‐mating sexual cannibalism can be a behavioural syndrome (i.e. a suboptimal personality) in which adaptive female aggression towards heterospecific prey spills over on non‐adaptive aggression towards courting males, independently of the female mating or feeding status (i.e. the ‘aggressive spillover hypothesis’, ASH). On the other hand, sexual cannibalism can also be a form of mate choice by which females selectively kill or mate with males depending on the male phenotype. We introduce the hypothesis that the most aggressive females in the population will not only attack males more frequently, but will be less likely to impose sexual selection on males through sexual cannibalism. Assuming that in a field common garden experiment in which females were fed ad libitum the rate of weight gain by a female may reflect her voracity or aggressiveness, we show that in the cannibalistic burrowing wolf spider Lycosa hispanica (formerly L. tarantula), voracity towards heterospecific prey predicts a female's tendency towards sexual cannibalism. Unmated females with higher weight gains were more cannibalistic and attacked males regardless of the male phenotype. On the other hand, females that were less voracious tended to be less cannibalistic, and when they did kill a male, they were selective, killing males in poorer condition and mating with those in better condition. Our results demonstrate that females with different phenotypes (growth rates) differently imposed selection on male condition, tentatively supporting the hypothesis that female aggression levels can spill over on sexual selection through sexual cannibalism.     

Swarming Behavior, Sexual Dimorphism, and Female Reproductive Status in the Sex Role-Reversed Dance Fly Species Rhamphomyia marginata

Dance flies are predaceous insects which often form male mating swarms. In many species males prior to swarming catch an insect prey, which is presented to the female at mating. In Rhamphomyia marginata, females in contrast to males gather to swarm, while males carrying a prey visit swarms for mating. Here I describe the swarming and courtship behavior in R. marginata and provide data on sexual dimorphism and swarming female reproductive status. Females swarm in small clearings in the forests. There was no specific swarm-maker. The swarming period lasted for 2–3 h and peaked around sunset. Identical swarm sites were used each evening and for several years. The mean number of females in swarms (swarm sites with at least one female) was 9.9 ± 9.1 (range, 1–40; n = 107) in 1993 and 7.1 ± 7.0 (range, 1–35; n = 68) in 1994. No obvious competition between females in swarms was observed. The operational sex ratio in swarms was extremely female biased (all swarms, 0.04). Less than one-third of male visits to swarms resulted in mating and males were found more often in larger swarms. Nuptial prey consisted of male midges. Females seem to mate more than once. Swarming females had undeveloped eggs, whereas mated females in swarms had further developed eggs than unmated females. Amount of sperm in the spermatheca was correlated with egg size. Amount of sperm and egg size did not correlate with wet weight, wing length, or wing load, except for egg size and weight. The wing coloration pattern and shape in R. marginata females are unique among dance flies, being greatly enlarged (1.6 times larger than that of males) and bicolored (gray part, 60% of wing area). When females, instead of males, possess extravagant secondary sexual characters, it is predicted from sexual selection theory that females should compete for males and that males should be selective in their choice of partner. A sex-role reversal will evolve when assess to males limit female reproductive success. The dance fly species R. marginata, like Empis borealis, another dance fly species studied earlier and discussed here, seems to fit these predictions.     

Influence of prey quality on the fitness of two phenotypes of Harmonia axyridis adults

The performance of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) adults of the aulica and nigra phenotypes fed on Aphis fabae Scopoli and Myzus persicae (Sulzer) was compared by measuring their voracity, daily biomass consumption, daily weight gain, efficiency of food utilisation, and reproductive capacity. Our results demonstrated differences in the suitability of A. fabae and M. persicae for the two phenotypes of the predator. This suggests that either differences occur in the nutritive requirements of the predators, or in the nutritive value of the two prey species. Both A. fabae and M. persicae supported the growth and oviposition of the aulica and nigra phenotypes. Although nigra females consumed fewer M. persicae, they achieved the same daily weight gain as aulica females. The predator phenotypes consumed the same amount of A. fabae, but the daily weight gain of aulica females was higher than that of nigra. The two predator phenotypes had the same feeding efficiency when consuming M. persicae or A. fabae. The reproductive capacity of nigra females was higher, when this phenotype consumed A. fabae rather than M. persicae.     

Functional response of larval and adult stages of Hippodamia variegata (Coleoptera: Coccinellidae) to different densities of Aphis fabae (Hemiptera: Aphididae)

We compare the efficiencies of different stages of Hippodamia variegata (Coleoptera: Coccinellidae) preying on Aphis fabae (Scolpoli) (Hemiptera: Aphididae) by estimating the functional responses of all stages. The experiments were carried out on leaf disks in petri dishes with 15-20 replicates. Our results revealed that all larval instars and adult males and females of H. variegata exhibited type II functional responses on different densities of prey. The rate of searching efficiency and handling time were estimated as 0.063 h(-1) and 6.933 h for first instar, 0.059 h(-1) and 3.343 h for second instar, 0.103 h(-1) and 1.909 h for third instar, 0.114 h(-1) and 0.455 h for fourth instar, 0.159 h(-1) and 1.194 h for male, 0.093 h(-1) and 0.409 h for female, respectively. Thus, handing time decreased from first instar to female. Handling times of males were significantly greater than those of females. The most effective stages of H. variegata were females, fourth instars, and males. The efficiency of females was nearly three times greater than that of males. The voracity of larval stages and male and female adults of H. variegata were estimated as 2.93, 5.85, 12.13, 45.13, 18.33, and 44.60 (aphids/d), respectively.     

DISTRIBUTION OF THE PYGMY RIGHT WHALE, CAPEREA MARGINATA, IN THE AUSTRALASIAN REGION

The latitudinal range of all records of sightings ( n = 9), and live strandings and carcasses ( n = 180) of Caperea marginata in the Australasian region was 32°00'–47°00'S. Records were concentrated on the edge of the South Australian gulfs, around Tasmania, at Stewart Island, in Cook Strait, and in the Auckland area. Limited data suggest that these may be related to planktonrich waters nearby. Body lengths ranged from 198 to 650 cm. Overall sex ratio was 0.70 (males: females). In regions north of about 41°S, juveniles (preweaning) made up 41% of the records and subadults (postweaning) were rare (13%). In regions south of about 41°S subadults (36%) were proportionately more abundant than juveniles (17%). Neonates were recorded from 35°37' to 47°00'S. Adults were found throughout the latitudinal range of the species in Australasia. The diet of the pygmy right whale included copepods and small euphausiids. Behavior consistent with feeding has been observed in coastal waters of Australia.     

Yeast communities of the cactusPilosocereus arrabidae as resources for larval and adult stages ofDrosophila serido

The feeding behavior ofDrosophila serido on the yeast communities of necrotic stem tissue ofPilosocereus arrabidae were studied in a sand dune ecosystem of Rio de Janeiro, Brazil. The prevalence of cactophilic yeasts includingPichia barkeri, Candida sonorensis andGeotrichum sp. in the crops and external surfaces ofD. serido reflected its association with the cactus habitat. The effective number of yeasts vectored on the surface of flies was higher than that in the crops. Also overlap between the yeasts from stems and from crops was partial suggesting selective feeding by the flies in the substrates visited. The females had a higher effective number of yeast species and a lower similarity than males with the yeast community ofP. arrabidae. This was probably related to the search for oviposition sites by females. The presence ofPichia thermotolerans-like andPichia amethionina varpachycereana in the flies, but not inP. arrabidae stems, indicated thatD. serido was not limited to this cactus species. The larvae and adults lived in different patches with the adults feeding in patches with higher yeast species richness. The larvae had a narrower feeding niche and higher overlap withP. arrabidae, and preferredP. barkeri andPichia cactophila as food. Adult flies fed on patches with the most frequent yeasts except forP. cactophila. Pichia caribaea was found in higher frequency in the adult crops than in the stems. Our data suggested that there was food selection and diet partitioning between adult and larval stages ofD. serido.     

Distinct feeding behavior between sexes of shape Frankliniella occidentalis results in higher scar production and lower tospovirus transmission by females

Feeding behavior and scar production of male and female F. occidentalis (Pergande) (Thysanoptera: Thripidae) were studied in relation to transmission of tomato spotted wilt tospovirus (TSWV). Electrical penetration graph (EPG) analysis showed that females feed more frequently and intensively than males. The feeding intensity, reflected by silvery scar production and studied by an image analysis system, demonstrated that females induced more numerous scars than males. At the same time, males transmitted TSWV with a higher efficiency than females, indicating that TSWV transmission and scar production are not positively correlated. Furthermore, males produced significantly more local lesions of TSWV than females. These quantitative differences in scar production and transmission of TSWV can be explained by the lower mobility and higher consumption rate of females. The influence of the sex-ratio on crop damage and virus transmission, and thus to the spread of TSWV, is emphasized.     

Sex and size related differences in the dry season feeding patterns of elephants in Chobe National Park, Botswana

Differences in feeding patterns of the African elephant were examined by sex and age during the dry season in a dystrophic savanna-woodland ecosystem in northern Botswana. Adult males had the least diverse diet in terms of woody plant species, but they consumed more plant parts than family units. The diameter of stems of food plants broken or bitten off was also greater for adult males than for females and subadult males. Adult males spent more time foraging on each woody plant than did females. The number of woody plant species and individuals present were higher at feeding sites of family units than at feeding sites of adult males, indicating that family units positioned themselves at feeding sites with higher species diversity than those of males. We argue that the most likely explanation for these differences is related to the pronounced sexual size dimorphism exhibited by elephants, resulting in sex differences in browsing patterns due to the allometric relationships that govern the tolerance of herbivores for variation in diet quality. From our results this Body Size Hypothesis is accepted rather than the alternative Scramble Competition Hypothesis, which predicts that adult male elephants consume lower quality browse because they are displaced from preferred browse as an outcome of scramble competition with adult females and their offspring. If the feeding patterns of adult male elephants were affected by intersexual scramble competition, we would expect adult males to browse at a higher level in the canopy than the smaller-bodied females and their offspring. No evidence was found for this, although adult females were found to browse at a higher level in the canopy when feeding in close proximity to subadults and juveniles than when feeding alone. Sex differences in elephant browsing patterns are, we propose, of relevance to understanding and managing elephant impacts on African woodlands.     

Does pirimicarb affect the voracity of the euriphagous predator, Coccinella undecimpunctata L. (Coleoptera: Coccinellidae)?

Pirimicarb is considered a selective and effective insecticide for the control of aphids and whiteflies. Coccinella undecimpunctata L. is a euriphagous predator autochthonous to the Azores, which feeds preferentially on aphids. The voracity of 4th instars and adults (males and females) of C. undecimpunctata using Aphis fabae Scopoli or Aleyrodes proletella L. as preys was evaluated in laboratory, as well as the impact of pirimicarb on the feeding performance using A. fabae as prey. In the absence of chemical treatment and when the prey was A. proletella, satiation lower limits were estimated on a density of 200 individuals in a 24-h period, for 4th instars, adult females and males of C. undecimpunctata. With A. fabae, satiation was attained when 200, 150 and 100 aphids were provided to 4th instars, adult females and males, respectively. C. undecimpunctata exhibited a type II functional response for both prey species. Fourth instars displayed a lower handling time than the adults; handling times of the adults where higher when A. fabae was the prey and attack rates were sex-dependent, that is, attack rate of females was higher on A. fabae while of males was higher on A. proletella. Voracity of C. undecimpunctata was not significantly affected by pirimicarb; therefore, the use of this insecticide can constitute a complementary component for the integrated management of A. fabae.