The influence of food supply on foraging behaviour in a desert spider
TL;DR: It is suggested that digestive constraints prevented supplemented spiders from fully utilizing the available prey, and by reducing foraging activities on the surface, spiders in a prey-rich habitat can reduce the risk of predation.
Abstract: We tested the alternative hypotheses that foraging effort will increase (energy maximizer model) or decrease (due to increased costs or risks) when food supply increased, using a Namib desert burrowing spider, Seothyra henscheli (Eresidae), which feeds mainly on ants. The web of S. henscheli has a simple geometrical configuration, comprising a horizontal mat on the sand surface, with a variable number of lobes lined with sticky silk. The sticky silk is renewed daily after being covered by wind-blown sand. In a field experiment, we supplemented the spiders' natural prey with one ant on each day that spiders had active webs and determined the response to an increase in prey. We compared the foraging activity and web geometry of prey-supplemented spiders to non-supplemented controls. We compared the same parameters in fooddeprived and supplemented spiders in captivity. The results support the "costs of foraging" hypothesis. Supplemented spiders reduced their foraging activity and web dimensions. They moulted at least once and grew rapidly, more than doubling their mass in 6 weeks. By contrast, food-deprived spiders increased foraging effort by enlarging the diameter of the capture web. We suggest that digestive constraints prevented supplemented spiders from fully utilizing the available prey. By reducing foraging activities on the surface, spiders in a prey-rich habitat can reduce the risk of predation. However, early maturation resulting from a higher growth rate provides no advantage to S. henscheli owing to the fact that the timing of mating and dispersal are fixed by climatic factors (wind and temperature). Instead, large female body size will increase fitness by increasing the investiment in young during the period of extended maternal care.
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01 Jan 2004
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TL;DR: An experiment to demonstrate whether an orb-web building spider, Argiope bruennichi modifies its web-building behavior after experiencing sensory information emitted by a UV recognizing flying insect, Bombus terrestris rejected the hypothesis that the spiders of the experimental group would increase investments in their web construction and stabilimentum decoration.
Abstract: Web structure of spiders is a foraging strategy as well as an investment to get prey. In order to increase the fitness consequence, spiders change their foraging strategy based on sensory information provided by prey species. We conducted an experiment to demonstrate whether an orb-web building spider, Argiope bruennichi modifies its web-building behavior after experiencing sensory information emitted by a UV recognizing flying insect, Bombus terrestris. To know how the web structure would be modified, we observed web characteristics after providing sensory information of a potential prey species, the bumblebee (experimental group) and compared them to the control group (no information provided). We hypothesized that the spiders of the experimental group would increase investments in their web construction and stabilimentum decoration. The results rejected our hypothesis. Web and stabilimentum constructions decreased in the course of the experiment in both the control group and the experimental group. The individuals did not increase their stabilimentum length and did not extend their web areas, in spite of sensory information given by the nectar collector.
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...비록 거미의 건축 행동은 진화적 구속에 의해 제한적인 양상을 보이지만 주어진 생물, 비생물적 환경 요인에 따라서 가변성을 보일 수 있다[7,9,10,12]....
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TL;DR: In this paper , an approach for area determination based on image processing was developed to determine the surface area of the buckspoor spider web of Seothyra schreineri, and the method rendered results that were considered valid and reliable.
01 Jan 2013
TL;DR: The results indicate that genetic effects on these animals are unlikely and suggest that organizational or early learning effects are significant determinants of pit-building behavior in this species.
Abstract: Environmental factors influencing pit-building behavior of the antlion Myrmeleon immaculatus are fairly well studied. The purpose of this study was to identify and differentiate environmental, genetic, and possible organizational or early learning factors influencing different behavioral phenotypes of two populations at Douglas Lake and Sturgeon Bay in northern Michigan, USA. We collected 60 antlions from each site and measured pit diameters in a common garden design. We distinguished treatments by feeding frequency, site, and day for a total of 22 days under a controlled laboratory setting with a regular disturbance regime. Sturgeon Bay antlions built larger pits that Douglas Lake antlions, animals that were subjected to a higher feeding frequency built smaller pits than a lower feeding frequency, and no apparent trend was gleaned from the day effect due to a presumed temperature effect. As a follow-up experiment we measured the effects of temperature on pit-building using light-bulb warming stations on 64 of our animals. Antlion pits that were given supplemental heat grew at a faster rate than controls. We also compared weight and pit diameters of at least 15 animals from seven sites between Sturgeon Bay and Pine Point. No significant difference was found between any site or lakeshore, though our data suggested that the original Sturgeon Bay study site displayed a larger pit size than any other site. These results indicate that genetic effects on these animals are unlikely, due to the close proximity of all populations. We suggest that organizational or early learning effects are significant determinants of pit-building behavior in this species.
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TL;DR: In this article, age and size at maturity at maturity number and size of offspring Reproductive lifespan and ageing are discussed. But the authors focus on the effects of age and stage structure on fertility.
Abstract: Prologue Part I: Evolutionary explanation Demography: age and stage structure Quantitative genetics and reaction norms Trade-offs Lineage-specific effects Part II: Age and size at maturity Number and size of offspring Reproductive lifespan and ageing Appendices Glossary References Author index Subject index.
10,338 citations
TL;DR: The book aims to instill in students an ability to think through biological research problems in such a way as to grasp the essentials of the experimental or analytical setup to know which types of statistical tests to apply in a given case and to carry out the computations required.
Abstract: This text develops the science of biometry from an elementary introduction up to the advanced methods necessary for biological research and for an understanding of the published literature. This text is aimed primarily at the academic biologist including general zoologists botanists microbiologists geneticists and physiologists in universities research institutes and museums. This book while furnishing ample directions for the analysis of experimental works also stresses the descriptive and analytical statistical study of biological phenomena. It is intended both as a text to accompany a lecture course and as a complete course for self-study. The book aims to instill in students an ability to think through biological research problems in such a way as to grasp the essentials of the experimental or analytical setup to know which types of statistical tests to apply in a given case and to carry out the computations required. Chapters cover biological data data handling descriptive statistics probability estimation and hupothesis testing analysis of variance linear regression correlation multiple and curvilinear regression analysis of frequencies and miscellaneous methods.
4,145 citations
Book•
04 Feb 1993
TL;DR: The spider in the ecological play is a central character in the story of how spiders avoid competition and the impact of spiders on insect populations and competitionist views of spider communities are examined.
Abstract: Preface Acknowledgements 1. The spider in the ecological play 2. Hungry spiders 3. Competitionist views of spider communities 4. Failure of the competitionist paradigm 5. How spiders avoid competition 6. Impact of spiders on insect populations 7. Anchoring the ecological web 8. Untangling a tangled web 9. Spinning a stronger story References Index.
914 citations
TL;DR: This paper presents a meta- Ecology of Insect Folivores of Woody Plants: Nitrogen, Water, Fiber and Mineral Considerations, andritional Ecology of Grass Foliage-Chewing Insects and Phytophagous Mites.
Abstract: Nutritional Ecology of Forb Foliage-Chewing Insects Nutritional Ecology of Insect Folivores of Woody Plants: Nitrogen, Water, Fiber and Mineral Considerations Nutritional Ecology of Grass Foliage-Chewing Insects Nutritional Ecology of Phytophagous Mites Nutritional Ecology of Lichen/Moss Arthropods Nutritional Ecology of Arthropod Gall-Makers Nutritional Ecology of Bruchid Beetles Nutritional Ecology of Seed-Sucking Insects Nutritional Ecology of Stored-Product Insects Nutritional Ecology of Stored-Product and House Dust Mites Ecology of Nectar and Pollen Feeding in Lepidoptera.
793 citations
"The influence of food supply on for..." refers background in this paper
...The short pauses in activity may occur because time is required to digest the prey or to renew the digestive enzymes before resuming foraging (Riechert and Harp 1987)....
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01 Jan 1991
TL;DR: Barth et al. as discussed by the authors observed that the physiognomy or physical structure of environments has an important influence on the habitat preferences of spider species, and ultimately on the composition of spider communities.
Abstract: Spiders are extremely common inhabitants of most terrestrial communities, yet, compared to other animal taxa, they have only recently become the subject of ecological research (Turnbull, 1973; Witt and Rovner, 1982; Wise, 1984; Shear, 1986; Nentwig, 1987, for reviews). From the earliest studies, it has been clear that the physiognomy or physical structure of environments has an important influence on the habitat preferences of spider species, and ultimately on the composition of spider communities. This is certainly no coincidental observation for two important reasons:
1.
Many spiders build webs for prey capture, and the attachment of these webs to surrounding structures often requires the presence of specific architectural features or arrangements (Riechert and Gillespie, 1986).
2.
The nature of both web-building and non-web-building spiders’ primary sensory modalities (they perceive vibration through mechanoreceptors) dictates that they perceive their environment using tactile and vibratory cues (Barth, 1985).
403 citations