1,720,984 research outputs found
Phylogenetics of Embioptera (=Embiidina)
No full textA morphological analysis using 70% of the described genera and 45% of the known species of Embioptera is described and discussed. The results indicate that many of the non-male terminalia characters are informative.Fil: Szumik, Claudia Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Edgerly Rooks, Janice. Santa Clara University; Estados UnidosFil: Hayash, Cheryl H.. Santa Clara University; Estados Unido
A new braconid genus (Hymenoptera) parasitizing webspinners (Embiidina) in Trinidad
Full text linkEarly in 1984, while conducting field studies on embiid behavior in the Arima valley of northern Trinidad, the junior author ob- served a braconid wasp ovipositing into the silk webs of an embiid, Clothoda urichi (Saussure) [Clothodidae]. The wasp and a paralyzed embiid were collected, and another wasp was successfully reared from that host. Specimens were sent to the senior author, then stationed at the National Museum of Natural History (USNM), who determined it to be a new braconid genus. A search of the USNM collection yielded no comparable specimens; however, during a subsequent search of the Museum of Comparative Zoology (MCZ) collection a specimen of a different, but related, species was found. Shenefelt (1980) provided a comprehensive index to recorded braconid hosts, which does not include any Embiidina. Callan (1952) mentioned that he collected numerous white cocoons from embiid webs in Trinidad, and he reared a braconid from these which was identified only as Apanteles sp. He suggested that these were parasites of lepidopterous larvae that sometimes live under the silk, not parasites of the webspinners. The establishment of this new genus as a parasite of webspinners therefore provides a totally new host order record for the family Braconidae
Colony composition and some costs and benefits of facultatively communal behavior in a Trinidadian webspinner (Embiidina: Clothodidae)
No full textlothoda urichi (Saussure), a Trinidadian webspinner, is facultatively communal; its colonies vary from solitary individuals to groups of reproductive females with their offspring sharing a silk covering. Communal females produce significantly more eggs than solitary females, but this increase is countered by significantly higher egg parasitism rates experienced by females reproducing under crowded conditions. C. urichi establishes colonies by remaining in its natal silk galleries, or by dispersing to establish a new gallery or to join an existing one. A model, developed by logistic regression analysis and based on the estimated area covered by silk, can be used to predict if a colony is solitary or communal, or whether half-grown nymphs are present
Is group living an antipredator defense in a facultatively communal webspinner?
No full textI tested whether predator attack rate is a function of expanse of silk for colonies ofAntipaluria urichi, a facultatively communal webspinner. The avoidance effect hypothesis predicts that the probability of a predator detecting a group does not increase proportionately with an increase in expanse of silk, and therefore, larger groups are relatively less likely to be attacked. I counted the number of holes inflicted on silk over 3 weeks, an indirect measure of predation, for 47 colonies. Supporting the avoidance effect, holes per perimeter of silk accumulated at a rate lower than would be predicted by size alone. Further analysis using predation risk, computed as holes per individual per silk perimeter, revealed that risk was extremely variable for colonies with little silk (\u3c200 cm) but, on average, did not vary as silk expanse increased. Overall, predators of webspinner colonies appear to be influenced by the avoidance effect, but whether the occupants of the silk are safer is unresolved
Choreography of silk spinning behavior in webspinners (Embioptera): phylogenetic signal or a microhabitat dance?
Full text linkSilk spinning defines the morphologically constrained embiopterans. All individuals spin for protection, including immatures, adult males and the wingless females. Enlarged front tarsi are packed with silk glands and clothed with ejectors. They spin by stepping with their front feet and releasing silk against substrates and onto pre-existing silk, often cloth-like. Spinning is stereotypical and appears to differ between species in frequency and probability of transition between two spin-step positions. This spinning choreography was assessed using thousands of spin-steps scored in the laboratory for 22 species to test (1) the body size hypothesis predicting that spinning would be more complex for larger species and (2) the phylogeny hypothesis which predicted that spinning would display phylogenetic signal. Tests relied on published phylogenies for the order Embioptera. Independent contrast analysis revealed relationships between five spin characteristics and body size, whereby, for example, larger webspinners invested in relatively larger prothoracic tarsi used for spinning and in spin-steps that would yield expansive silk coverings. Spin-step dynamics displayed phylogenetic signal for the frequency of six spin-steps and for 16 spin-step transitions. Discussion focuses on patterns revealed by analysis of phylogenetic signal and the relationship to life style and to recently discovered chemical characteristics of silk
Life Beneath Silk Walls: A Review of the Primitively Social Embiidina
Full text linkI review and summarize the scattered information on embiids (Order Embiidina), with an emphasis on details of colony structure and maternal care. I summarize experimental and observational field results from a detailed study on parental and communal behavior of Antipaluria urichi, a Trinidadian webspinner. Topics discussed include the function of maternal behavior, interactions with egg parasitoids, antipredator attributes of communal living, and possible functions of silk. I also compare features of webspinner sociality to other communal insects and spiders. In addition, I discuss promising topics for future study, including male dimorphism, the possibility of higher sociality, and communication systems
Maternal behaviour of a webspinner (Order Embiidina): mother–nymph associations
No full text1. The life cycle of Antipaluria urichi (Saussure) (Embiidina: Clothodidae) was aseasonal and without overlap of generations within fifteen closely monitored colonies observed over a 9½ month field season. Adult females remained with their nymphs after hatch but disappeared prior to maturation of their offspring. 2. Time budgets of nymphs and their mothers differed significantly. Adult females spent significantly more time spinning silk than their offspring. After the nymphs hatched, the increase in area of the silk covering approximated an exponential curve, reflecting the increase in silk spinning behaviour exhibited by the adult female. These results indicate that silk may be a major contribution of the mother. 3. Observations suggest that silk protects embiids from some predators and from rainfall, which is often torrential in the rainforest. 4. In experimental field colonies, nymphs with their mothers developed significantly faster than those alone, indicating that maternal behaviours promote the development of their nymphs
Lichens, Sun, and Fire: A Search for an Embiid-Environment Connection in Australia (Order Embiidina: Australembiidae and Notoligotomidae)
Full text linkThis investigation is the first to quantify the degree of habitat specialization for any species within the little-known order Embiidina. The lichen and plant communities found in the habitats of two sympatric species, one living on lichens encrusted on granite and another feeding in leaf litter, were characterized using a process of ordination and cluster analysis. Differences among 40 samples and their relationships to environmental factors were probed statistically using Spearman’s coefficient of rank correlations generated by comparing rank similarity matrices of the census sites. The lichen eater, Notoligotoma hardyi (Friederichs), was more abundant in areas with strong southern exposures and was associated with higher lichen abundance. They preferentially grazed on particular lichens, the first indication that an embiid shows specialization in feeding. The detritivore, Australembia incompta Ross, was closely associated with particular plant communities, especially those less susceptible to fire. Their colonies were more common in rockier, coastal areas and less abundant in grasslands and habitats dominated by Eucalyptus. Insight into ecological variation within the order can guide further exploration of other traits (such as silk structure and function and primitive social behavior) in this rarely studied group of insects
Course-based campus environmental research projects
Full text linkCampus administrators and faculty across the country are realizing the educational and economic value of campus greening. Many administrators have established clear environmental campus policies in an effort to recognize the economic value of green institutional operations and to respond to the need for adopting sustainable practices. Faculty and students have contributed to the green movement by integrating the physical campus into the educational process. At many institutions, students have led efforts to implement environmentally friendly, and in some cases, economically sensible practices particularly in the areas of energy conservation and waste management. Faculty and students have worked together on class projects and independent research to contribute to the greening movement. Many institutions have a legacy of environmental consciousness that began in the early 1970s. At Santa Clara University (SCU), in Santa Clara, California, greening has occurred more recently with the start of an Environmental Studies program in 1992 and a Campus Environmental Assessment in 1995. A strong driving force for greening of the campus has been student and faculty interest manifested primarily as coursebased campus projects. This article discusses some outcomes of environmental research conducted by students and faculty in chemistry, biology and anthropology. Some avenues are suggested for enhancing the research experience and for incorporating significant findings into the University\u27s modus operandus
Choreography of silk spinning by webspinners (Insecta: Embioptera) reflects lifestyle and hints at phylogeny
Full text linkSilk spinning defines the morphologically constrained embiopterans. All individuals spin for protection, including immatures, adult males and the wingless females. Enlarged front tarsi are packed with silk glands and clothed with ejectors. They spin by stepping with their front feet and releasing silk against substrates and onto preexisting silk, often cloth-like. Spinning is stereotypical and appears to differ between species in frequency and probability of transition between two spin-step positions. This spinning choreography was assessed using thousands of spin-steps scored in the laboratory for 22 species to test: (1) the body size hypothesis predicting that spinning would be more complex for larger species; and (2) the phylogeny hypothesis which predicted that spinning would display phylogenetic signal. Tests relied on published phylogenies for the order Embioptera. Independent contrast analysis revealed relationships between five spin characteristics and body size, whereby, for example, larger webspinners invested in relatively larger prothoracic tarsi used for spinning and in spin-steps that would yield expansive silk coverings. Spin-step dynamics displayed a phylogenetic signal for the frequency of six spin-steps and for 16 spin-step transitions. Discussion focuses on patterns revealed by analysis of phylogenetic signal and the relationship to life style and to recently discovered chemical characteristics of silk
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