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Many orb-web building spiders add conspicuous, white silk decorations termed stabilimenta onto the central portion of the webs. Stabilimenta are known to vary greatly in form and quantity from species to species, and also within a species. In the present study, stabilimentum variations in form and quantity are described, and the factors influencing stabilimentum variations in Argiope versicolor from Singapore, in both the field and the laboratory, are examined. Our results from field survey and laboratory experiments show that: (1) the form and occurrence of stabilimenta varied with developmental stage of spiders: A. versicolor juveniles (body length: < 0.6 cm) built disc-like (discoid) stabilimenta while adults spun cross-like (cruciform) stabilimenta; (2) the quantity of stabilimenta (percentage of stabilimentum area covering the web to the web area) decreased with increasing web size and spider size; (3) light intensity affected the density and percentage cover of stabilimentum on the web: A. versicolor tend to build more and denser stabilimenta in dim conditions than in bright surroundings; (4) well-fed A. versicolor adults added more stabilimenta than starved spiders. These findings suggest that A. versicolor may adjust the frequency and quantity of stabilimenta to suit multiple functions, specifying the circumstances under which to use each function (conditional stabilimentum-building strategies).

Argyrodes Simon 1864 is a large, cosmopolitan theridiid genus whose members exhibit a wide range of foraging techniques which usually involve exploiting other spiders, either by using their webs, stealing their food, or preying on them directly. We held a symposium on this genus at the 15th International Congress of Arachnology, Badplaas, South Africa in order to obtain a clearer perspective on the relationship between the phylogeny of the genus and the different foraging techniques. We concluded that Argyrodes forms a monophyletic group within the Theridiidae, and that there are clear monophyletic clades within the genus (already identified as species groups) that appear to share behavioral characteristics. We found no clear indication that foraging behaviors such as kleptoparasitism (stealing food) evolved from araneophagy (eating spiders) or vice versa. However, it appears that species that specialize in either kleptoparasitism or araneophagy use additional techniques in comparison to species that readily use both foraging modes. During our examination of Argyrodes/host interactions we noted the importance of Nephila species as hosts of Argyrodes species around the world and the impact of Argyrodes on Nephila. We also noted the fluid nature of the relationship between Argyrodes and the spiders with which they interact. For example, an Argyrodes/host relationship can change to an Argyrodes/prey relationship, and the type of kleptoparasitic behavior employed by an Argyrodes can change when it changes host species. The importance of eating silk was also noted and identified as an area for further research. We concluded that more work involving international collaboration is needed to fully understand the phylogeny of the genus and the relationships between the different types of foraging behaviors.

In the present study, the combined effects of temperature and diet on development and survival of a crab spider, Misumenops tricuspidatus (Fabricius) (Araneae: Thomisidae) in laboratory conditions were investigated. The experiments were carried out at five constant temperatures ranging from 15°C to 35°C on two kinds of diets, fruit flies ( Drosophila melanogaster ) and a mixed diet of fruit flies and dung flies. It was found that development rate of eggs increased with successive temperature increments, reaching a maximum at 30°C, then declined at 32°C and that eggs survived well between 20°C and 30°C (>70%), but no eggs survived to hatching at 35°C regardless of whether the spiders were fed on single or mixed diet. Juveniles completed development on both diets at all constant temperatures tested, but survival was low at the extreme temperatures. Juvenile development times decreased over successive temperature increments up to 30°C, then increased at 32°C. Females developed faster than males. Diet also influenced development time, survival and number of moults to reach maturity. Juveniles raised on the mixed diet composed of fruit flies and dung flies developed faster, survived better, and required fewer moults to reach maturity than on a diet composed of only fruit flies. Plots of development rates (reciprocal of mean development times) and survival rates (expressed as percentages) against constant temperatures indicated that M. tricuspidatus is well adapted to low temperatures, but detrimentally affected by high temperatures. Using linear regression, the lower development threshold (LDT) and the sum of effective temperatures (SET) for all life stages of M. tricuspidatus on each diet were estimated. LDT and SET varied among developmental stages and between diets.

In order to resolve better the deep relationships among salticid spiders, we compiled and analyzed a molecular dataset of 169 salticid taxa (and 7 outgroups) and 8 gene regions. This dataset adds many new taxa to previous analyses, especially among the non-salticoid salticids, as well as two new genes – wingless and myosin heavy chain. Both of these genes, and especially the better sampled wingless, confirm many of the relationships indicated by other genes. The cocalodines are placed as sister to lapsiines, in a broader clade with the spartaeines. Cocalodines, lapsiines, and spartaeines are each supported as monophyletic, though the first two have no known morphological synapomorphies. The lyssomanines appear to be non-monophyletic, of three separate groups: (1) Lyssomanes plus Chinoscopus, (2) Onomastus, and (3) the remainder of Old World species. Several previously-inferred relationships continue to be supported: hisponines as sister to the Salticoida, Amycoida as sister to the remaining Salticoida, and Saltafresia as monophyletic. The relationship of Salticus with Philaeus and relatives is now considered well enough corroborated to move the latter into the subfamily Salticinae. A new clade consisting of the Plexippoida + Aelurilloida + Leptorchesteae + Salticinae is recognized. Nungia is found to be an astioid, and Echeclus, Gedea and Diplocanthopoda to be hasariines. The euophryines are corroborated as monophyletic. The agoriines Agorius and Synagelides are salticoids, within the sister group to amycoids, but their further placement is problematical, perhaps because of their nuclear ribosomal genes’ high GC bias, as also seen in the similarly problematic Eupoa.

Although many salticid spiders have been shown to have corneas that transmit ultraviolet light (UV). Whether the corneas of non-salticid spiders transmit UV has not been previously investigated. In this study, we determined the spectral corneal transmission properties of 38 species belonging to 13 non-salticid families. We used these data to estimate the T50 transmission cut-off value, the wavelength corresponding to 50% maximal transmission for each species. The corneas of almost all species from the families Deinopidae, Lycosidae, Oxyopidae, Pisauridae, Sparassidae and Thomisidae, all of which have been reported to rely to a substantial extent on vision, transmitted short wavelengths below 400 nm, ranging from 306 to 381 nm. However, species from the families Atypidae and Ctenizidae are not known to rely substantially on vision, and the corneas of these species tended to absorb light of wavelengths below 380 nm, which may not allow UV sensitivity in these spiders. Liphistiidae, the family widely regarded as most basal among spiders, is of particular interest. The species in this family are not known to make substantial use of vision, and yet we found that liphistiid corneas transmitted UV light with a low T50 value (359 nm). T50 values of non-salticid spider corneas also varied with light habitat. Species living in dim environments tended to have UV-opaque corneas, but species inhabiting open areas had UV-transmitting corneas. However, there was no evidence of corneal transmission properties being related to whether a species is diurnal or nocturnal.

Background Taxa may respond differently to climatic changes, depending on phylogenetic or ecological effects, but studies that discern among these alternatives are scarce. Here, we use two species pairs from globally distributed spider clades, each pair representing two lifestyles (generalist, specialist) to test the relative importance of phylogeny versus ecology in predicted responses to climate change. Methodology We used a recent phylogenetic hypothesis for nephilid spiders to select four species from two genera (Nephilingis and Nephilengys) that match the above criteria, are fully allopatric but combined occupy all subtropical-tropical regions. Based on their records, we modeled each species niche spaces and predicted their ecological shifts 20, 40, 60, and 80 years into the future using customized GIS tools and projected climatic changes. Conclusions Phylogeny better predicts the species current ecological preferences than do lifestyles. By 2080 all species face dramatic reductions in suitable habitat (54.8–77.1%) and adapt by moving towards higher altitudes and latitudes, although at different tempos. Phylogeny and life style explain simulated habitat shifts in altitude, but phylogeny is the sole best predictor of latitudinal shifts. Models incorporating phylogenetic relatedness are an important additional tool to predict accurately biotic responses to global change.

Lay Summary Proactive animals are assumed to make quicker but inaccurate decisions. However, this does not seem to be the case for one species of jumping spider with high cognition ability. In this study, we tested the existence of aggressiveness in this jumping spider species and found that, in the prey choice decision-making, more aggressive individuals were more likely to make fast decisions but they also performed as accurately as less aggressive individuals.

Arthropod sampling protocols have been applied to four areas of undisturbed rainforest in Australia and Borneo at sites located between 28° S and 4° N. Seven different trapping methods have been used in each case following a strictly comparable protocol applied during single wet-season surveys at each location. A number of large scale patterns across sites correlated with latitude, altitude and/or biogeographical history are evident at the ordinal level. The results are used to evaluate two key ideas in biodiversity survey. The first tests questions of the constancy of particular trap types in terms of the target animals. The second attempts to design an efficient multiple method sampling 'package' for rapid biodiversity assessment. Across all sites similar traps behaved in a similar manner in terms of the profile of arthropods that they caught although Malaise traps and pitfalls are particularly 'constant' in this regard. Subsets of both trapping methods and target taxa are identified which will maximise the opportunities for detecting between site differences.

Capture techniques and preferences of Zenodorus durvillei (Walckenaer), Z. metallescens (L. Koch) and Z. orbiculatus, Australian salticids that feed on ants in nature, were studied in the laboratory using a wide variety of ants and other insects. Each species adopted three prey‐capture modes: ambush, active pursuit in the open, and gleaning from spider webs. Large ants were sometimes stabbed several times before holding on. A variety of methods were used for testing preference. The potential of using this assortment of methods for assessing strength of preferences is discussed. Each species took dolichoderine, formicine, myrmecine, myrmicine and pseudomyrmecine ants in preference to a variety of other insects (aphids, bugs, caterpillars, crickets, flies, lacewings, mantises, mayflies, midges, mosquitoes, moths, plant and leaf hoppers, and termites). Testing with laboratory‐reared spiders showed that the development of preference for ants and ant‐specific prey‐capture behaviour did not depend on p...

Phaeacius malayensis (Salticidae: Spartaeinae) is an atypical jumping spider that routinely includes other jumping spiders in its diet. This paper presents the first detailed study of P. malayensis' prey preferences. Three basic types of tests of prey preference were used: different types of prey were provided on alternate days (alternate-day tests), two types of prey were provided simultaneously (simultaneous-presentation tests), and an alternative prey type was provided while the predator was already feeding (alternative-prey tests). In alternate-day and simultaneous-presentation testing, but not in alternative-prey testing, (i) P. malayensis preferred spiders (salticids and hunting spiders) to insects; (ii) P. malayensis preferred salticids to hunting spiders; (iii) these preferences were not exhibited in some paired choices when the background was nonmatching, indicating that visual concealment is important with respect to some, but not all, prey; (iv) P. malayensis' prey preferences were not affected by a prior 14-day period without food; (v) after 21 days of fasting, P. malayensis took different types of prey indiscriminately. The adaptive significance of preferences for particular types of prey is discussed in the context of optimal-foraging theory.

Phaeacius malayensis (Salticidae: Spartaeinae) is an atypical jumping spider that routinely includes other jumping spiders in its diet. This paper presents the first detailed study of P. malayensis' prey preferences. Three basic types of tests of prey preference were used: different types of prey were provided on alternate days (alternate-day tests), two types of prey were provided simultaneously (simultaneous-presentation tests), and an alternative prey type was provided while the predator was already feeding (alternative-prey tests). In alternate-day and simultaneous- presentation testing, but not in alternative-prey testing, ( i) P. malayensis preferred spiders (salticids and hunting spiders) to insects; (ii) P. malayensis preferred salticids to hunting spiders; ( iii) these preferences were not exhibited in some paired choices when the background was nonmatching, indicating that visual concealment is important with respect to some, but not all, prey; (iv) P. malayensis' prey preferences were not affected by a prior 14-day period without food; (v) after 21 days of fasting, P. malayensis took different types of prey indiscriminately. The adaptive significance of preferences for particular types of prey is discussed in the context of optimal-foraging theory. Resume : Phaeacius malayensis (Salticidae : Spartaecinae) est une araignee sauteuse atypique qui consomme couram- ment d'autres araignees sauteuses. Les preferences de P. malayensis pour certaines proies sont decrites ici en details. Trois types de tests ont servi a evaluer les preferences : differents types de proies presentes tous les 2 jours (tests des jours en alternance), deux types de proies presentes en meme temps (test des presentations simultanees), ou un type de proie presente alors que le predateur est deja en train de se nourrir (test de presentation d'une proie de rechange). Le test des jours en alternance et le test des presentations simultanees, mais pas le test de la proie de rechange, ont de- montre que (i) P. malayensis prefere les araignees (Salticides et araignees chasseuses) aux insectes; ( ii) que P. malayen- sis prefere les araignees sauteuses aux araignees chasseuses; (iii) que ces preferences ne s'expriment pas lorsque le substrat est contrastant, ce qui indique que le camouflage est important pour certaines proies, mais pas pour toutes; (iv) que les preferences de P. malayensis pour certaines proies ne sont pas affectees par un jeune prealable de 14 jours et (v) qu'apres 21 jours de jeune, P. malayensis consomme indifferemment n'importe quelle proie. L'importance evolu- tive des preferences pour des types particuliers de proies est examinee dans le contexte de la theorie de la quete opti - male. (Traduit par la Redaction) 2226

Parental care, especially as it relates to our understanding of sociality, is a topic that has received considerable recent attention in research on spiders (Aviles, 1997). Predatory strategies, including foraging decisions, prey preferences and predatory versatility, have also been emphasized in the recent literature. The present paper is concerned with both of these areas, parental care and predatory strategies. Scytodes sp. indet. is a versatile predator that captures prey either in its web or away from webs, and prey capture may be either by ambush or by active pursuit regardless of whether in the presence and absence of webs. The web is a sparsely woven sheet across a concave upper leaf surface, with a three-dimensional tubular nest linked to the sheet via a small opening. Leaves may be green and living or brown and dead. In the field, a wide range of insects and spiders is taken, but jumping spiders (Salticidae) are the dominant prey. Predatory attacks are by spitting, with large prey being spat at repeatedly before being subdued. After spitting, the scytodid wraps prey in silk before feeding. Eggs are enclosed in a silk egg sac. The female uses her chelicerae to hold her eggs until hatching. After hatching, there is an extended mother–offspring association, with juveniles tending to remain in their mother's web until after the third moult. Females take prey to their juveniles and either feed alongside the juveniles or leave the juveniles to feed alone.

Peer-reviewed articles are the foundation of modernecological science. An essential component of mostecology papers is a clear, well-crafted argument thatbuilds upon the existing research base within the subjectarea in question and substantiates important assump-tions, technical information and opinions by accuratelyidentifying (i.e. citing) the source material.Despite the central role of citing references in thewriting of research papers, there have been no studies todate that assess the suitability and fidelity of citations inecology journals. Anecdotal evidence certainly suggeststhat citation malpractice is widespread. Many of us haveencountered instances where the support of an assertionby the cited reference proves to be ambiguous, non-existent, or even contradictory (often we only noticethis when our own work has been mis-cited!). A relatedpractice is the citing of ‘‘empty’’ references (Harzing2002), also known as ‘‘lazy author syndrome’’ (Gavras2002), where the citation actually attributes a finding oran opinion to a secondary source such as a review paper,editorial, etc. But how pervasive is citation malpracticeand how can it be controlled?We randomly selected three papers from each of thetwo most recent issues (prior to April 2006) of 51journals listed under ‘‘Ecology’’ in the Science CitationIndex (all with an impact factor 1) to examine theappropriateness and accuracy of citations used. Fromeach of the 306 papers (the ‘‘primary articles’’) we thenselected randomly one citation from the reference list(the ‘‘cited article’’) and identified the assertion it waspurportedly supporting. To avoid ambiguity we onlyused assertions supported by a single citation and, toreduce potential bias from especially errant authors,only one citation per primary article was selected. Thecited article was then obtained and examined carefully(independently by three of the authors: PT, DY andLD) and its appropriateness was categorised into one offour groups by a majority decision (Table 1). At allstages of the study, papers obtainable only through theNational University of Singapore digital library systemwere used. As just six articles per journal were selected,among-journal trends were not examined.We found that the original assertion was ‘‘clearlysupported’’ by the citation in 76.1% of the cases; thesupport was ‘‘ambiguous’’ in 11.1% of the cases; andthe citation did ‘‘not support’’ the original statement in7.2% of the cases. The remaining 5.6% of the caseswere classified as ‘‘empty’’. How do these mis-citationrates compare with other disciplines? One well-pub-licised example from physics and engineering (Ball2002, Muir 2002, Simkin and Roychowdhury 2003)analysed how misprinted citations are propagatedthrough the scientific literature and concluded that asmany as 80% of all cited papers are not read by theauthors citing them (Simkin and Roychowdhury 2003).This result, however, is most probably an overestima-tion (copying citations from other sources is notnecessarily associated with whether those papers haveactually been read). A number of biomedical studieshave used an approach similar to our own, althoughthey applied the analogous categories ‘‘major error’’ and‘‘minor error’’ rather than ‘‘no support’’ and ‘‘ambig-uous’’. Combined error rates found by Fenton et al.2000 (17%) and Lukic´ et al. 2004 (19%) are compar-able to our result of 18.3% for ‘‘no support’’ plus‘‘ambiguous’’, though other results for medical journalsrange from 12.3% (Gosling et al. 2004) to 35.2%(Goldberg et al. 1993). To our knowledge, emptycitation data are absent for all the sciences.Various proximate factors could be responsible formisappropriation of citations. Many instances will begenuine mistakes where the article has been misread ormisunderstood or, through the long process of writing a

In Los Banos in the Philippines (Laguna, Luzon), Scytodes sp. indet. is a web-building spitting spider (Scytodidae) that preys primarily on jumping spiders (Salticidae) and Portia labiata is an aggressive-mimic jumping spider that preys especially frequently on Scytodes. Tactics by which three species of Portia (P. africana, P. fimbriata, and P. labiata) and, for Portia labiata, three disjunct populations (Sri Lanka and, in the Philippines, Sagada and Los Banos) capture this especially dangerous prey are compared. Local adaptation to Scytodes by the Los Banos P. labiata is discussed. The Los Banos P. labiata uniquely made consistent use of tactics (soft plucking with palps and signal–detour–leap sequences) that were apparently responsible for greater prey-capture success and more effective avoidance of being spat on. Inter- and intraspecific differences were evident despite having used Portia that were reared in the laboratory with no prioir experience with scytodids.

Siler sp., Euophrys sp. 1 and 2, and six species of Chalcotropis feed on ants in nature. Capture techniques and preferences of each species were studied in the laboratory using a wide variety of ants and other insects. Siler sp. usually attacked ants, but not other insects, from directly behind. Euophrys sp. 1 and 2 consistently attacked ants, but not other insects, head on. Chalcotropis attacked large ants head on, but there was no particular orientation of attacks on small ants or on other prey regardless of size. All species tended to stab ants, but not other prey, several times before holding on. In three types of prey‐preference tests, each of the nine salticid species took dolichoderine, formicine, myrmicine, ponerine, and pseudomyrmecine ants in preference to a variety of other insects (aphids, bugs, caterpillars, cockroaches, crickets, flies, gnats, lacewings, mantises, may flies, midges, mosquitoes, moths, plant and leafhoppers, plant lice, and termites). Testing with laboratory‐reared s...

The influence of diet on survival rate and growth was investigated in Portia fimbriata, an araneophagic salticid spider in Queensland. Portia fimbriata spiderlings were reared on one of three different diets: spiders only, insects only, and a mixture of spiders and insects. For each diet, various spider and insect species were used, and the spider diets included as prey both cursorial salticid species and web-building species. Individuals on the insects-only diet did not survive past the fifth instar, whereas juveniles reached maturity when raised on the other diets. Survivorship of P. fimbriata raised on the spiders-only diet was significantly higher when they were fed on the mixed diet. Diet treatment had a significant effect on body dimensions measured at the fourth instar and at maturity. In addition, P. fimbriata reared on the spiders-only diet reached sexual maturity earlier than those reared on the mixed diet. These results suggest that there are fitness-related consequences of prey specialization in P. fimbriata.

Females of Euryattus sp. indet., a salticid from Queensland, suspend rolled-up leaves for nests. Euryuffus males respond to conspecific females in nests with vibratory courtship. Portiafimhriara, a sympatric aalticid that preys on E~qyaftus, responds to Euryurrus females’ nests by mimicking the courtship of Euyaftu.~ males. In the laboratory, cues by which potential mates (conspecific males) and potential predators (P. jfimbriuta females) recognize the nests of Euryaffus females are investigated experimentally. Both the position of the leaf in relation to the substratum and the number of threads between the leaf and the substratum appear lo be important cues by which both the Euryattus males and P. fimbriata females find nests. In addition, chemical cues from Euryattus females influence conspecific males, but there is no evidence that chemical cues are important to the predator.

Prey‐preference behaviour of three species of araneophagic salticid (P. labiata from the Philippines and Sri Lanka, P. africana from Kenya and Uganda, and P. schultzi from Kenya) is studied in the laboratory for the first time. “Well‐fed” (7 day fast) and “starved” (14 day fast) males and females of each species have a pronounced preference for web‐building spiders over insects, and a less pronounced preference for salticid spiders over insects. Also, well‐fed and starved males and females of these species prefer web‐building spiders to salticids. Preferences for taxonomic type of prey are the same regardless of whether living, active prey or dead, motionless lures are used, suggesting that all these araneophagic salticids can distinguish between the different taxonomic categories of prey without reference to their different movement patterns. For each species, females—relative to males—preferred larger prey. When extra‐starved (21 day fast), males and females of all species appeared to take prey...

Under natural and sexual selection traits often evolve that secure paternity or maternity through self-sacrifice to predators, rivals, offspring, or partners. Emasculation-males removing their genitals-is an unusual example of such behaviours. Known only in insects and spiders, the phenomenon's adaptiveness is difficult to explain, yet its repeated origins and association with sexual size dimorphism (SSD) and sexual cannibalism suggest an adaptive significance. In spiders, emasculation of paired male sperm-transferring organs - secondary genitals - (hereafter, palps), results in 'eunuchs'. This behaviour has been hypothesized to be adaptive because (i) males plug female genitals with their severed palps (plugging hypothesis), (ii) males remove their palps to become better fighters in male-male contests (better-fighter hypothesis), perhaps reaching higher agility due to reduced total body mass (gloves-off hypothesis), and (iii) males achieve prolonged sperm transfer through severed genitals (remote-copulation hypothesis). Prior research has provided evidence in support of these hypotheses in some orb-weaving spiders but these explanations are far from general. Seeking broad macroevolutionary patterns of spider emasculation, we review the known occurrences, weigh the evidence in support of the hypotheses in each known case, and redefine more precisely the particular cases of emasculation depending on its timing in relation to maturation and mating: 'pre-maturation', 'mating', and 'post-mating'. We use a genus-level spider phylogeny to explore emasculation evolution and to investigate potential evolutionary linkage between emasculation, SSD, lesser genital damage (embolic breakage), and sexual cannibalism (females consuming their mates). We find a complex pattern of spider emasculation evolution, all cases confined to Araneoidea: emasculation evolved at least five and up to 11 times, was lost at least four times, and became further modified at least once. We also find emasculation, as well as lesser genital damage and sexual cannibalism, to be significantly associated with SSD. These behavioural and morphological traits thus likely co-evolve in spiders. Emasculation can be seen as an extreme form of genital mutilation, or even a terminal investment strategy linked to the evolution of monogyny. However, as different emasculation cases in araneoid spiders are neither homologous nor biologically identical, and may or may not serve as paternity protection, the direct link to monogyny is not clear cut. Understanding better the phylogenetic patterns of emasculation and its constituent morphologies and behaviours, a clearer picture of the intricate interplay of natural and sexual selection may arise. With the here improved evolutionary resolution of spider eunuch behaviour, we can more specifically tie the evidence from adaptive hypotheses to independent cases, and propose promising avenues for further research of spider eunuchs, and of the evolution of monogyny.

The prey-catching techniques and prey preferences of Habrocestum pulex (Hentz), ant-eating jumping spider (Araneae: Salticidae) from North America, were studied in the laboratory. H. pulex uses prey-specific, prey-catching behaviour against ants. Ants, but not other insects, were consistently attacked head-on. After attacking an ant, but not after attacking other insects, H. pulex kept its forelegs extended laterally and forwards without touching the ground. H. pulex feeds on ants in preference to other insects. Preference for ants and prey-specific predatory behaviour do not depend on prior experience with ants. As in earlier studies of other ant-eating salticids, three different types of tests for prey preference were carried out, using active, living prey: Type 1 (one type of prey presented to salticid at a time on alternate days); Type 2 (two types of prey presented to salticid simultaneously); and Type 3 (salticid feeding on one type of prey presented with alternative prey of another type). However, newly-designed apparatus made testing more efficient. Preference for ants over other insects is shown not to depend on level of activity or any other cues from prey movement pattern: Type 1 and Type 2 tests were carried out using motionless (dead) lures, and again ants were taken in preference to other insects. Findings from this study are discussed in relation to recent findings on other ant-eating salticids.

We review previously published studies on how temperature affects development and reproduction of spiders, with an emphasis on recent studies from China published in Chinese. We apply both linear and non-linear models to data from these papers to examine relationships between temperature and the spider's rate of development, and we estimate the thermal requirements of selected species. Intra-and interspecific variation in development time, survival, adult longevity, adult size, and reproduction are considered, and apparently, phenotypic plasticity in these above life history traits is induced by growth temperature. With respect to the life histories and life style of the spider spicies we argue that the thermal adaptations of spiders might have important roles in fine-tuning the species' life-history strategies: much of this variability is probably a consequence of adaptations to the different thermal conditions prevailing in the natural habitats of these species. Spiders living in warmer climates can withstand higher temperatures than species from colder climates, and species from colder climates can tolerate lower temperatures than species from warmer climates. Cold-habitat species develop more slowly at high temperatures, and warm-habitat species develop more slowly at low temperatures. Also, different species of spiders show different seasonal adaptations to the microenvironments in which they live: fast, low-temperature development is an indicator of adaptation to colder season(s) of the year, whereas slow, low-temperature development and fast, high-temperature development are indicators of adaptation to warm season(s) of the year.

Portia fimbriata from Queensland, a previously studied jumping spider (Salticidae), routinely includes web-building spiders and cursorial salticids in its diet, both of these types of prey being dangerous and unusual prey for a salticid. The present paper is the first detailed study ofP. fimbriata's prey preferences. Three basic types of tests of prey preference were used, providing evidence that (1)P. fimbriata males and females prefer spiders (both web-building spiders in webs and salticids away from webs) to insects; (2)P. fimbriata males and females prefer salticids to web-building spiders; (3)P. fimbriata males and females prefer larger spiders to smaller spiders; (4) there are intersexual differences in the preferences ofP. fimbriata for prey size, females preferring larger prey and males preferring smaller prey; and (5)P. fimbriata's prey preferences are not affected by a prior period without food of 2 weeks. When preferences were tested for by using both living, active prey and dead, motionless lures, the same preferences were expressed, indicating thatP. fimbriata can distinguish among different types of prey independent of the different movement patterns of different prey.

Development and survival of an erigonine spider, Erigonidium graminicolum (Sundevall) (Araneae: Linyphiidae), were studied at seven constant temperatures ranging from 15°C to 35°C. Plotting development rates (reciprocal of mean times for development) and survival rates (expressed as percentages) against the different constant temperatures indicated that E. graminicolum is well adapted to low temperatures, but sensitive to high temperatures. Juvenile development occurred over a wide range of constant temperatures, but the survival rate was low at the upper and lower extremes. All eggs died before hatching at the highest tested temperature (35°C). There were statistically significant differences between males and females in juvenile and pre-imaginal development times. Juvenile development time decreased as temperature was raised to 32°C, but increased at 35°C. The mean duration of pre-imaginal development (egg to adult) varied from 94.4 d at 15°C to 23.8 d at 32°C. Considering development rate and survival, the most favourable temperature range appeared to be 15–32°C. For all life stages, graphs obtained by plotting the reciprocal of development times against temperature could be described by the six-parameter rate function of Wang et al. (1982). Temperature-independent distributions of normalized development times were approximated by a cumulative Weibull function. Frequency distributions of development times changed with temperature; they were almost uniform at 15–20°C, more symmetrical at 25–28°C, and somewhat skewed to the right at 30–32°C. The sum of effective temperatures (SET), and lower development threshold (LOT), were established for all life stages of E. graminicolum. Survivorship curves varied with temperature and, on average, were Type III.

Males of sexually cannibalistic spiders commonly mutilate parts of their paired genitals (palps) during copulation, which may result in complete emasculation or the ‘eunuch phenomenon’. In an orb-web nephilid spider, Nephilengys malabarensis , about 75 per cent of males fall victim to sexual cannibalism, and the surviving males become half-eunuchs (one palp emasculated) or full-eunuchs (both palps emasculated). While it has been shown that surviving eunuchs are better fighters compared with intact males when guarding the females with which they have mated, mechanisms behind eunuchs’ superior fighting abilities are unknown. The previously proposed ‘gloves-off’ hypothesis, attributing eunuchs’ enhanced locomotor endurance to the reduction in total body weight caused by genital mutilation, is plausible but has remained untested. Here, we tested the gloves-off hypothesis in N. malabarensis by comparing the time until exhaustion (i.e. endurance) of intact males with half- and full-eunuchs created experimentally. We found that by reducing body weight up to 4 per cent in half-eunuchs and 9 per cent in full-eunuchs through emasculation, endurance increases significantly in half-eunuchs (32%) and particularly strongly in full-eunuchs (80%). Our results corroborate the gloves-off hypothesis and further point towards the adaptive significance of male emasculation.

Many spiders possess myrmecomorphy, and species of the jumping spider genusMyrmarachneexhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods.

The jumping spiderCosmophasis umbraticafrom Singapore is strongly sexually dimorphic. The males, but not the females, reflect ultraviolet as well as green–orange light. The scales responsible for this are composed of a chitin–air–chitin sandwich in which the chitin layers are three-quarters of a wavelength thick and the air gap a quarter wavelength (whereλ=600 nm, the peak wavelength of the principal reflection maximum). It is shown that this configuration produces a second reflectance peak at approximately 385 nm, accounting for the observed reflection in the ultraviolet. Other scales have a similar thickness of chitin but lack the air gap and thus produce a dull purple reflection. This novel mechanism provides the spiders with two colour signals, both of which are important in mating displays.

Chemoreception is a key feature in selection of host plant by phytophagous insects, and odorant-binding proteins (OBPs) are involved in chemical communication of both insects and vertebrates. The legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae) is one of the key pest species of cowpea and widely distributed throughout tropical and subtropical regions, causing up to 80% of yield loss. In this study, we investigated the electrophysiological responses of female M. vitrata to floral volatiles from V. unguiculata. Seventeen electroantennogram-active compounds were identified from floral volatiles of V. unguiculata by coupled gas chromatography-electroantennography (GC-EAD) and gas chromatography-mass spectrometry (GC-MS). Then, we cloned two novel full-length GOBP genes (MvitGOBP1 and MvitGOBP2) from the antennae of M. vitrata using reverse transcription PCR. Protein sequence analysis indicated that they shared high sequence similarity with other Pyralididae insect GOBPs and had the typical six-cysteine signature. Real-time PCR analysis indicated that MvitGOBP1-2 mRNA was highly expressed in the antennae of female adult with several thousands-fold difference compare to other tissue. Next, the recombinant MvitGOBP1-2 was expressed in Escherichia coli and purified using Ni ion affinity chromatography. Fluorescence binding assays demonstrated that MvitGOBP1-2 had different binding affinities with 17 volatile odorant molecules including butanoic acid butyl ester, limonene, 4-ethylpropiophenone, 1H-indol-4-ol, butanoic acid octyl ester and 2-methyl-3-phenylpropanal. In the field trapping experiment, these six floral volatiles could effectively attract female moths and showed significant difference compared with the blank lure. These results suggested that MvitGOBPs and the seventeen floral volatiles are likely to function in the olfactory behavior response of female moths, which may have played crucial roles in the selection of oviposition sites. The six compounds that we have identified from the volatiles of V. unguiculata may provide useful information for exploring efficiency monitoring and integrated pest management strategies of this legume pod borer in the field.

Many orb-weaving spiders decorate their webs with extra, bright white, ultraviolet light reflecting silk. Previous studies suggest that these decorations increase a spider's foraging efficiency by improving web attractiveness, which is known as the prey-attraction hypothesis. One assumption of this hypothesis is that individuals which decorate their webs at a higher frequency are expected to have a higher growth rate. Using a decoration-building orb-weaving spider, Argiope versicolor , I show a strong positive relationship between the growth rate in terms of weight gain and the frequency of decoration-building, as well as the rate of insect interception. This is the first study to reveal a fitness consequence of decorating behaviour in spiders.

Previous studies have shown that animals may make adaptive adjustments in response to chemical cues from predators, but hatching responses to diet-related chemical cues from predators have not been previously demonstrated. In the system studied here, the predator is an araneophagic jumping spider (Salticidae), Portia labiata, and the prey organism is a subsocial spitting spider, Scytodes pallida (Scytodidae). The spitting spider carries its eggs in its chelicerae, and carrying eggs is known to make it more vulnerable to predators. It is also known from an earlier study that the prior diet of the predator alters how dangerous the individual predator is to the spitting spider. In the experiments reported here, incubation time was shorter when volatile cues from the predator were present and longer in control tests when no chemical cues from the predator were present. The previous predator's diet also influenced incubation time: when in the presence of volatile cues from individuals of P. labiata that had previously fed on individuals of S. pallida, incubation time was shorter than when in the presence of volatile cues from individuals of P. labiata that had been feeding instead on house flies.

This paper (i) reviews temperature/development rate relationships in plants and poikilothermic invertebrates, (ii) argues that the relationship is often linear over much of the range up to the thermal optimum (T o ) and provides a possible mechanism, (iii) provides evidence of a trade-off between the base temperature (T b ) and the thermal constant (DD) that enables each species to adapt to its thermal environment, and (iv) indicates some of the practical and ecological implications. Where a linear relationship has been characterised it is possible to estimate the base temperature for development (T b , expressed in °C) and the thermal constant for development (DD, the reciprocal of the temperature coefficient (a), expressed in degree [°C] days accumulated above T b ). A possible basis for the linear relationship between rate and temperature is proposed based on the Arrhenius and Sharpe-Schoolfield equations involving activation enthalpy and progressive inactivation of the reactant molecules at both low and high temperatures. Knowledge of T b and DD enables rates of development of organisms/ processes to be calculated and compared at any given temperature between T b and T o . An analysis of published results for differentiation processes (differentiation = a change of state) in species of insects, Collembola, spiders, nematodes and plants showed that T b tended to vary with the temperature of the niche to which the organism is adapted, and that there was a trade-off between T b and DD. Tropical species had higher values of T b than temperate and DD decreased as T b increased (and vice versa). This conferred a competitive advantage on each species in the thermal environment to which it was adapted. The decrease in DD tended to be relatively greater than the increase in T b further favouring a high T b in tropical species. A mechanism for the trade-off is suggested whereby DD and T b were shown to be correlated (P < 0.01) with the activation enthalpy (H A ) of an assumed, rate-limiting enzyme. Thermal time can also be applied to processes involving growth (= an increase in dry weight) when the DD requirement for development to maturity is the sum of the requirements for differentiation and growth. Rates of both differentiation and growth can vary greatly between species, depending upon the niche they inhabit, and the implications of such differences for resource requirements are considered. In insects and nematodes, but not in annual plants, development is usually coupled to growth. Consequently, when resources are inadequate, mature size in these animals varies less than in plants. Thermal time is shown to provide insight into the life strategies of species within their communities and to have practical implications.

The carrying of eggs often renders parents vulnerable to predators due to increased conspicuousness or decreased mobility. Nonetheless, egg-carrying parents can escape from the predators to which they are vulnerable. Previous studies have demonstrated heavy predation by spider-eating jumping spiders (Portia labiata) on egg-carrying spitting spider (Scytodes pallida) females, but little predation on eggless females. If the timing of hatching is phenotypically plastic, then both S. pallida females and their eggs could reduce the risk of predation by hatching early. Hence, this study examines the hatching responses of S. pallida to chemical cues from P. labiata, both in the laboratory and in the field, and addresses the following questions. (i) Do cues from predatory P. labiata influence the hatching traits of S. pallida? (ii) Are the olfactory cues from predators sufficient for predator detection by S. pallida ? (iii) Are hatching responses to predatory P. labiata controlled by egg-carrying S. pallida females, or directly by their embryos? The study provides evidence of hatching as a life-history switch point, which shows an adaptive plasticity in response to predation risk in egg-carrying S. pallida. Egg-carrying S. pallida females, but not unattended eggs, adjust egg-hatching time (the interval between oviposition and hatching) in response to the threat of predation on both the female and her eggs by P. labiata. In the presence of P. labiata, eggs that are carried by females hatch sooner; the hatchlings of these eggs are therefore smaller than hatchlings born in the absence of P. labiata. Chemical cues that are released from the draglines of P. labiata are sufficient to elicit changes in the egg-hatching traits of S. pallida. Hatching early in response to this predator may benefit both females and their offspring. To my knowledge, this is the first direct experimental study to demonstrate predator-induced hatching plasticity in spiders and, in particular, in animals with parental care.

Paracyrbawanlessiis a southeast Asian jumping spider (Salticidae) that lives in the hollow internodes of fallen bamboo and preys on the larvae, pupae and adults of mosquitoes. In contrast toEvarchaculicivora, an East African salticid that is also known for actively targeting mosquitoes as preferred prey, there was no evidence ofP.wanlessichoosing mosquitoes on the basis of species, sex or diet. However, our findings show thatP.wanlessichooses mosquitoes significantly more often than a variety of other prey types, regardless of whether the prey are in or away from water, and regardless of whether the mosquitoes are adults or juveniles. Moreover, a preference for mosquito larvae, pupae and adults is expressed regardless of whether test spiders are maintained on a diet of terrestrial or aquatic prey and regardless of whether the diet includes or excludes mosquitoes. Congruence of an environmental factor (in water versus away from water) with prey type (aquatic versus terrestrial mosquitoes) appeared to be important and yet, even when the prey were in the incongruent environment,P.wanlessicontinued to choose mosquitoes more often than other prey.

The extent to which decision-making processes are constrained in animals with small brains is poorly understood. Arthropods have brains much smaller and simpler than those of birds and mammals. This raises questions concerning limitations on how intricate the decision-making processes might be in arthropods. At Los Banos in the Philippines, Scytodes pallidus is a spitting spider that specialises in preying on jumping spiders, and Portia labiata is a jumping spider that preys on S. pallidus. Scytodid spit comes from the mouth, and egg-carrying females are less dangerous than eggless scytodids because the female uses her chelicerae to hold her eggs. Held eggs block her mouth, and she has to release them before she can spit. The Los Banos P. labiata sometimes adjusts its tactics depending on whether the scytodid encountered is carrying eggs or not. When pursuing eggless scytodids, the Los Banos P. labiata usually takes detour routes that enable it to close in from behind (away from the scytodid's line of fire). However, when pursuing egg-carrying scytodids, the Los Banos P. labiata sometimes takes faster direct routes to reach these safer prey. The Los Banos P. labiata apparently makes risk-related adjustments specific to whether scytodids are carrying eggs, but P. labiata from Sagada in the Philippines (allopatric to Scytodes) fails to make comparable risk-related adjustments.

Conspicuous behaviour exposes animals to predation; prey–attraction thus often conflicts with antipredator behaviour. The fact that a conspicuous ultraviolet–light reflecting silken structure in the orb–webs of certain spider species, known as a stabilimentum, makes the webs obvious to both prey and predators has been used to argue that spiders benefit from building stabilimenta by attracting prey and/or defending against visually hunting predators. Here, we provide experimental evidence that stabilimenta can act as visual signals that attract web–invading spider–eating predators with acute vision to the webs. We also show that the predators can learn to remember a particular type of stabilimentum. Thus, stabilimentum–building spiders risk a high level of predation by attracting visually hunting predators.

Abscondita, a new genus of fireflies from South-east Asia, is described from males and females of Abs. anceyi (Olivier 1883), Abs. cerata (Olivier 1911), Abs. chinensis (L. 1767), Abs. perplexa (Walker 1858), Abs. promelaena (Walker 1858) and Abs. terminalis (Olivier 1883), all transferred from Luciola Laporte. Both L. dubia Olivier 1903 and L. dejeani Gemminger 1870 are synonymised with Luciola perplexa (Walker), and L. aegrota Olivier 1891 and L. melaspis Bourgeois 1909 with L. promelaena Walker. Females are characterised by their bursa plates. Larvae are associated and described for Abs. anceyi (Olivier), Abs. chinensis (L.) and Abs. terminalis (Olivier). Taxonomic issues regarding the identification of species with very similar colouration of pale dorsum and black tipped elytra are addressed and in some cases resolved. A neotype for Luciola chinensis (L.) is erected and Luciola praeusta (Kiesenwetter 1874) is synonymised with L. chinensis (L.). Descriptions of life histories, biology and flashing patterns of populations of Abs. chinensis and Abs. terminalis from central China are included. A bs. terminalis is the first Asian firefly known to possess multiple flash trains where males are documented to display with repeating flash trains.

Animal colour signals used in intraspecies communications can generally be attributed to a composite effect of structural and pigmentary colours. Notably, the functional role of iridescent coloration that is 'purely' structural (i.e., absence of pigments) is poorly understood. Recent studies reveal that iridescent colorations can reliably indicate individual quality, but evidence of iridescence as a pure structural coloration indicative of male quality during contests and relating to an individual's resource-holding potential (RHP) is lacking. In age- and size-controlled pairwise male-male contests that escalate from visual displays of aggression to more costly physical fights, we demonstrate that the ultraviolet-green iridescence of Cosmophasis umbratica predicts individual persistence and relates to RHP. Contest initiating males exhibited significantly narrower carapace band separation (i.e., relative spectral positions of UV and green hues) than non-initiators. Asymmetries in carapace and abdomen brightness influenced overall contest duration and escalation. As losers retreated upon having reached their own persistence limits in contests that escalated to physical fights, losers with narrower carapace band separation were significantly more persistence. We propose that the carapace UV-green iridescence of C. umbratica predicts individual persistence and is indicative of a male's RHP. As the observed UV-green hues of C. umbratica are 'pure' optical products of a multilayer reflector system, we suggest that intrasexual variations in the optical properties of the scales' chitin-air-chitin microstructures are responsible for the observed differences in carapace band separations.

Background Males usually produce mating plugs to reduce sperm competition. However, females can conceivably also produce mating plugs in order to prevent unwanted, superfluous and energetically costly matings. In spiders–appropriate models for testing plugging biology hypotheses–mating plugs may consist of male genital parts and/or of amorphous covers consisting of glandular or sperm secretions. In the giant wood spider Nephila pilipes, a highly sexually dimorphic and polygamous species, males are known to produce ineffective embolic plugs through genital damage, but nothing is known about the origin and function of additional conspicuous amorphous plugs (AP) covering female genitals. Methodology We tested alternative hypotheses of the nature and function of AP in N. pilipes by staging mating trials with varying degrees of polyandry. No APs were ever formed during mating trials, which rules out the possibility of male AP formation. Instead, those females that oviposited produced the AP from a liquid secreted during egg sac formation. Polyandrous females were more likely to lay eggs and to produce the AP, as were those that mated longer and with more total insertions. Our further tests revealed that, in spite of being a side product of egg sac production, AP, when hardened, prevented any subsequent copulation. Conclusions We conclude that in the giant wood spider (Nephila pilipes), the amorphous mating plugs are not produced by the males, that repeated copulations (most likely polyandrous) are necessary for egg fertilization and AP formation, and that the AP represents a female adaptation to sexual conflict through prevention of unwanted, excessive copulations. Considering the largely unknown origin of amorphous plugs in spiders, we predict that a similar pattern might be detected in other clades, which would help elucidate the evolutionary interplay of various selection pressures responsible for the origin and maintenance of mating plugs.

No animals are known to possess both ultraviolet (UV) reflectance and fluorescence that are sex-specific. We provide evidence for this separation in the jumping spider Cosmophasis umbratica, which has UV reflectance and UV-induced green fluorescence restricted to males and females, respectively. During courtship, many of the studied pairs failed to show typical display posturing when UV light was blocked. Occluding the UV component of sunlight to only one of each pair also caused atypical behavior: Females showed no interest in non‐UV-reflective courting males, and males either ignored or were lackluster in courting nonfluorescing females. These results demonstrate the importance of both sex-specific hues as sexual signals for effective intraspecific communication.