Reproductive ecology of predaceous Heteroptera

Reproductive ecology entails relating the physiology and behavior of an organism to its environment and the community in which it lives. Terrestrial predatory Heteroptera (including Anthocoridae, Geocoridae, Miridae, Nabidae, Pentatomidae, Phymatidae, and Reduviidae) display a wide range of reproductive ecologies. But in spite of this variability, a review of the literature reveals certain underlying trends that are useful in understanding how generalist predators function within their environments. First, the reproductive ecology of predatory bugs is inherently coupled to the physiology of the female and her eggs. Second, three population parameters are directly tied to reproduction (maturation rates, realized fecundity, and reproductive diapause) have great bearing on the rate of population increase and reproductive success of a predatory bug, but these three parameters fluctuate widely within and among species. The variables that affect these processes include the physiological status of the mother (mating status, age and size, and nutritional status), the abiotic environment in which she and her eggs live (temperature, photoperiod, water availability), and natural enemies that attack eggs and reproductive females. A final trend observed in the literature involves the hierarchy of events that must occur before a female finds a suitable oviposition site. Females all must locate preferred habitats, plants/substrates, and microsites in which to insert or deposit an egg, but they use a variety of tactics and cues in order to accomplish this, depending on their life history traits. Examining the factors that constrain and promote the reproductive potential of predatory Heteroptera will make biological control programs that center on them more reliable and sustainable.     

STUDY ON THE KARYOTYPES OF THREE SPECIES OF GENUS CARBULA (HETEROPTERA: PENTATOMIDAE)

Abstract  The karyotypes and meiotic behaviors of three Carbula species ( Carbula obtusangda Reuter, C. putoni (Jakovlev)and C. sinica Hsiao et Cheng) were studied. Karyotype analyses using specific software were made and model karyotype chart was presented. All three species have the typical diploid Chromosome number of 14 for the family Pentatomidae and X-Y sex chromosomal mechanism, but the behavior of autosomes and sex-chromosomes during meiosis among three species are different, and one or two supeeruumerary chromosomes were detected in C. putoni . These characteristics may provide some useful clues on the study of pentatomid taxonomy and phylogeny.     

Development and comparison of trunk traps to monitor movement of Halyomorpha halys nymphs on host trees

Halyomorpha halys Stål (Hemiptera: Pentatomidae) has recently become a major orchard pest in the Mid‐Atlantic, USA. Large H. halys populations can develop on wild tree hosts adjacent to orchards, posing an ongoing threat to fruit. Adults and nymphs feed on tree fruit, causing economic injury. Understanding the seasonal patterns of nymphal host use among trees at the orchard‐woodland interface may aid the development of integrated pest management strategies for this pest. In laboratory and field experiments, modified versions of published trap designs – ‘Circle’, ‘Hanula’, ‘M&M’ (after Moeed & Meads) traps – were compared for their effectiveness for capturing H. halys nymphs walking up and down tree trunks. In the laboratory, second instars were released at the top and bottom of ailanthus (tree of heaven), Ailanthus altissima (Mill.) Swingle (Simaroubaceae), logs and captures were recorded after 24 h. Circle and M&M traps, respectively, were most effective for capturing nymphs walking up and down. In the field, traps were deployed on ailanthus trees next to apple orchards and captures were recorded weekly from 24 July to 11 September 2013. As in the laboratory, Circle and M&M traps captured the greatest number of upward‐ and downward‐walking nymphs. Hanula traps were least effective in both experiments. In the field, 88% of total captures were of nymphs walking up trees. This was at least partially explained by behavioral assays in the laboratory demonstrating that nymphs exhibited negative gravitaxis and positive phototaxis. Stage‐specific trends in captures of instars walking up during field sampling were observed. These results suggest that trunk traps can be used to address important ecological questions about seasonal patterns of host use by H. halys nymphs.     

Waveform characterization of the soybean stem feeder Edessa meditabunda: overcoming the challenge of wiring pentatomids for EPG

Stink bugs (Hemiptera: Heteroptera: Pentatomidae) are in general robust and restless insects, which makes them difficult to wire for electropenetrograph (EPG) studies. In addition, cuticular lipids may reduce wire effectiveness, and their removal could improve success of wiring. We compared wiring effectiveness for three species of stink bugs, differing in walking behaviour and degree of cuticular waxiness, that is, Piezodorus guildinii (Westwood), Nezara viridula (L.), and Loxa deducta (Walker). Results indicated that removal of cuticular lipids by mechanical abrasion (via sanding) greatly improved attachment success with gold wire. Our hypothesis that heavier and bigger bugs would lose the wire attachment more quickly than lighter and smaller bugs was not confirmed, regardless of the sanding. In contrast, our hypothesis that greater movement of a bug would cause the wire to break more often was supported by extensive testing. Behaviour appears to be more relevant for successful wiring than body weight. We used the sanding and wiring technique to characterize and correlate direct current EPG waveforms for the large and restless stem‐feeding stink bug Edessa meditabunda (Fabricius) on soybean plants. This marks the first published example of pentatomid EPG waveforms. Edessa meditabunda recordings on soybean stems generated eight types of waveforms in three phases and two families, named as follows: non‐probing = Np and Z; pathway phase = Em1; X wave phase = X; ingestion phase, family I = Em2 and Em3; ingestion phase, family N = Em4 and Em5. These eight were described based on their frequencies, relative amplitudes, and level voltages. Histological studies of stylets within salivary sheaths correlated the Em1, Em2, and Em3 waveforms with specific penetration sites. The waveform with the longest duration when feeding was Em2, representing xylem sap ingestion; in addition, waveform Em3 (always preceded by an X wave) was correlated with phloem sap ingestion.     

Some like it hot! Rapid climate change promotes changes in distribution ranges of Nezara viridula and Nezara antennata in Japan

We compared past and current limits of the distribution range of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), in central Japan. In the early 1960s, the northern limit of the range was in Wakayama Prefecture and was limited by a +5 °C isothermal line for the mean January temperature. In 2006–2007, a new survey demonstrated that this northern limit had shifted northwards by 85 km (i.e., at a mean rate of 19.0 km per decade). The shift was most likely promoted by milder winter conditions. The mean January to February temperature in the region was 1.03–1.91 °C higher in 1998–2007 than in 1960–1969. The number of cold days (with the mean temperature below +5 °C) also significantly decreased, while the annual lowest temperature significantly increased. Nezara viridula was found mostly close to those locations where (i) the mean January temperature exceeded +5 °C, (ii) the mean number of cold days did not exceed 26 in January to February, and (iii) where the mean annual lowest temperature did not drop below –3.0 °C. The general linear model shows that the mean January temperature and number of cold days are the most important factors controlling the northern limit of distribution of N. viridula. All the climatic data suggest that over the last 45 years, environmental conditions have become more favourable for overwintering of N. viridula at many locations in central Japan. This has probably promoted the northward spread of the species, representing a direct response to climate warming. A sympatrically distributed congeneric, Nezara antennata Scott, seems to respond to the warming by a retreat from the ocean coast towards cooler elevated habitats, which might be a complex response to elevated temperature and interspecific mating with N. viridula. It is suggested that the range changes in both species will continue in response to further climate change.     

真蝽属一新种（半翅目：蝽科）

本文记述蝽科真蝽属一新种：拟太白真蝽Ｐｅｎｔａｔｏｍａ ｐａｒａｔａｉｂａｉｅｎｓｉｓ ｓｐ．ｎｏｖ．,新种与太白真蝽Ｐｅｎｔａｔｏｍａ ｔａｉｂａｉｅｎｓｉｓ Ｚｈｅｎｇ ｅｔ Ｌｉｎｇ相似。模式标本存于南开大学生物系。     

Performance of nymphal and adult southern green stink bug on an overwintering host plant and impact of nymph to adult food-switch

Performance of nymphs and adults of the southern green stink bug,Nezara viridula (L.) (Heteroptera: Pentatomidae) feeding on immature fruits of radish,Raphanus raphanistrum L. (Brassicaceae) was poor compared with feeding on immature soybean [Glycine max (L.) Merrill] pods, but a change from radish to soybean from nymph to adult alleviated some of the detrimental effects of this food on adult performance. Over 50% of nymphs died on radish, while only 15% died on soybean. To complete nymph development (stadia 2 through 5), male and female nymphs required 9.5 and 13.3 days longer on radish compared to soybean. Fresh body weight of 1-d-old adult females and males was ≅65% greater for those reared as nymphs on soybean than on radish, with females being significantly heavier than males on both foods. Survivorship and longevity of females, however, was greater for those fed on radish as nymphs and as adults, as compared to those that fed on soybean or radish followed by soybean. Males lived longer when fed exclusively on soybean. In general, reproductive performance and percentage gain in adult body weight was greatest for insects fed on soybean only, and were better for those whose food was switched from nymph to adult, as compared to those insects fed on radish solely.     

Dispersion of flightless adults of the Asian lady beetle, Harmonia axyridis, in greenhouses containing cucumbers infested with the aphid Aphis gossypii: effect of the presence of conspecific larvae

Nezara viridula (L.) (Heteroptera: Pentatomidae) recently expanded its distribution range in Japan and reached Osaka. In the southern temperate zone, the species overwinters in the adult stage and reproductive diapause is associated with a body colour change from green to russet. In Osaka, the reproductive diapause is only induced in September–October and nymphs from late egg masses are destined to die during winter. However, the fate of adults emerging late in the season remained unknown. Survival, body colour change, and post‐diapause reproduction were studied under quasi‐natural conditions in Osaka in 1999–2000 in those adults that attained adulthood as late as in November. Two experimental cohorts were used: in the Outdoor cohort, insects were reared outdoors starting in their second instar (28 September); in the Laboratory cohort, nymphs and subsequently adults were reared from the same day under diapause‐inducing conditions (L10:D14 at 25 °C), then acclimatized (5 days at 20 °C and 5 days at 15 °C; L10:D14) and transferred outdoors on 1 December. Adults in both cohorts did not reproduce in autumn and survived the winter with a low mortality. More than 20% of adults in the Outdoor cohort failed to change body colour from green to russet during winter, apparently because of the low ambient temperature, suggesting that the environmental conditions required for colour change do not completely coincide with those required for diapause induction, and that the colour of the adults is not always a reliable indicator of diapause in this species. After overwintering, females from the Outdoor cohort produced significantly fewer egg masses and eggs and had a significantly shorter period of oviposition than females that entered diapause under short‐day conditions in the Laboratory cohort. Thus, if progeny from the late egg masses attain adulthood late in the autumn, these adults have high chances of successful overwintering, but their reproductive output after the winter diapause is significantly reduced.     

蝽科精巢细胞减数分裂染色体行为及其反映的属种间亲缘关系

为探讨蝽科精巢细胞减数分裂各时期染色体形态和行为差异, 以及据此反映的属种间亲缘关系, 采用常规染色体制片法对蝽科6属9种精巢细胞减数分裂各期染色体形态特征、 行为及精子的形成进行了观察和比较研究。结果表明： 蝽科精巢细胞为交叉型减数分裂, “O”型交叉为其典型交叉减数分裂形式。各属种减数分裂各期染色体行为相似, 但形态不同。减数分裂各期染色体形态、 排列方式, 中期染色体相对长度、 组成与核型以及精子形态等特征具有属种间差异性。蝽科精巢细胞中期Ⅰ染色体组平均相对长度都为12.5, 在进化过程中染色体组长度信息总量不变。基于染色体相对长度的聚类分析结果显示, 菜蝽属Eurydema、 麦蝽属Aelia、 珠蝽属Rubiconia和条蝽属Graphosoma亲缘关系密切, 而二星蝽属Stollia与果蝽属Carpocoris关系较近。     

卷蝽Paterculus elatus(Yang)的细胞学研究(半翅目:蝽科)(英文)

本文研究了中国蝽科昆虫──卷蝽 Ｐａｔｅｒｃｕｌｕｓ ｅｌａｔｕｓ（Ｙａｎｇ）的核型并采用核型分析软件对第一次减数分裂终变期的染色体进行了该型分析。结果表明：卷蝽的２ｎ＝１６,具有ＸＹ性别决定机制,具有一对ｍ－染色体,在有些细胞中出现一个超量染色体。