Aglaoctenus Lagotis Research Articles

Utilizing spiders for biomonitoring air pollution from road traffic: a novel approach and preliminary findings.

Polycyclic aromatic hydrocarbons (PAHs) are air pollutants generated mainly by fuel combustion, industry, and other anthropogenic sources. The level of these pollutants can be assessed by employing biomonitors, a cost-effective and less contaminating alternative than conventional methods. In the present study, we aimed to investigate whether spiders inhabiting areas around a major city like Córdoba, Argentina, adsorb and retain PAHs in their exoskeletons. Additionally, we aimed to determine if spiders' life traits influence their capacity to accumulate PAHs and explore potential relationships between PAH levels and the types of roads where they were collected. Specimens of a funnel-shaped web spider (Aglaoctenus lagotis) and an orb-weaver (Metepeira spp.) were collected from roadsides. Roads were classified into four categories based on their traffic intensity. Using high-performance liquid chromatography (HPLC), we identified 15 different PAHs. Both species exhibited varying concentrations of PAHs, although Metepeira spp. showed 15-18 times higher PAH levels compared to A. lagotis. Moreover, A. lagotis individuals living alongside highways accumulated up to six times more PAHs compared to those along other road types. These findings suggest that spiders' life traits may influence pollutant concentrations. Our study demonstrates that spiders near roads are exposed to and accumulate PAHs on their exoskeletons, likely sourced from petrogenic vehicular emissions, highlighting their value as biomonitors and emphasizing the need for mitigation measures to address air pollutants emitted from mobile sources.

Should I stay or should I fly: Aerial dispersal in a funnel‐web wolf spider from the grasslands of southern South America

AbstractBallooning is a mechanism of aerial dispersal present in some groups of spiders. By releasing silken threads that are blown by the wind, spiders can travel long distances through the air. Aglaoctenus lagotis is a wolf spider that lives its entire life associated with a funnel‐web, despite the wandering habit that characterizes species in this family. We can find two forms of the species in Uruguay, one of them a strict inhabitant of grasslands of Uruguay. The high habitat specificity and the spiderlings observed surrounding the maternal web suggest a low aerial dispersal capacity in this species. In this study, we tested whether A. lagotis spiderlings are capable of dispersing by ballooning. We conducted laboratory and field experiments during the day and night, to record the occurrence of ballooning and typical behaviours that precede ballooning. We recorded ballooning both in the laboratory and in the field, and it was more frequent during the day. Although it has been reported repeatedly in species from this family, we never observed the pre‐ballooning tip‐toeing behaviour in A. lagotis. Ballooning was preceded by dropping on dragline, considered a behaviour that could generate aerial dispersion of lesser distance than that generated by the tip‐toeing. In this paper, we shall discuss the implications of this form of aerial dispersal, considering that the species analysed is a web wolf spider.

Not the same: phylogenetic relationships and ecological niche comparisons between two different forms of Aglaoctenus lagotis from Argentina and Uruguay

Not the same: phylogenetic relationships and ecological niche comparisons between two different forms of Aglaoctenus lagotis from Argentina and Uruguay

Can't even trust the family? The web of the unusual web-building wolf spider Aglaoctenus lagotis (Araneae: Lycosidae) invaded by typical wandering wolf spiders

Spider webs can be invaded by other species of spiders. While the majority involve spiders that build webs of their own, there are reports of wandering spiders invading webs. Most wolf spiders (Lycosidae) do not build webs and web invasion behaviour has never been reported in this family. Here, we report wandering wolf spiders invading webs of Aglaoctenus lagotis, one of the few wolf spiders that build webs. We collected observations of ten web invasions by the wandering species Lycosa erythrognatha, L. poliostoma, and Schizocosa malitiosa. We discuss the possible implications of these invasions for moulting and speculate that the webs are safe refuges.

Male performance and associated costs in successive sexual encounters in a polygynous web wolf spider

Polygynous males increase their reproductive success by fertilizing as many females as possible. However, this strategy can lead to costs for the males. This study focused on an atypical wolf spider that lives in webs, Aglaoctenus lagotis. Previous studies report polyandrous females, but little is known about the mating strategy of males and its potential associated costs. Our goals were to determine the potential polygyny and the changes in sexual behaviour, body condition and physiology of males throughout successive matings. Males were expected to mate with multiple females; males’ body condition was expected to decrease and male mating performance, including sperm transfer, was expected to decrease over successive matings. Males were exposed to successive virgin females every 3 days until the male did not court, was cannibalized or died of natural causes. Agreeing with our predictions, males were capable of multiple matings, showing an average of 5 ± 2 matings (range 3–11). Their mating performance decreased in successive matings and, although no changes were found in the behavioural patterns during the courtship over successive matings, the number of palpal insertions decreased. Unexpectedly, overall body condition did not decrease and males did not deplete their sperm supply. We found that 44% of the males were victims of sexual cannibalism after their third mating. The females that attacked or cannibalized males had less sperm stored in their spermathecae than those that did not. We discuss hypotheses that may clarify this scenario and the role of the cryptic female choice mechanism.

Different levels of polyandry in two populations of the funnel-web wolf spider Aglaoctenus lagotis from South America

Populations of a species may show variation in mating systems, especially when the species is widely distributed. Aglaoctenus lagotis is a funnel-web wolf spider distributed in South America and with a ‘central Argentina form’ (CA) and a ‘southern Uruguay form’ (SU). Both forms differ in sexual behaviour, population density and copulatory season. This study evaluates the potential level of polyandry of both forms, sequentially exposing females to different males of their form under laboratory conditions. The number of copulations each female accepted and the characteristics of these sexual encounters were registered. CA females accepted more re-copulations than SU females and seemed to maintain more sexual attractiveness after the first copulation. In neither form was female re-copulation influenced by body characteristics, duration of the first copulation, ejaculation frequency or copulatory body shaking of females. Additionally, the PCA showed that both forms could be separated by their copulation behaviours. The higher level of polyandry in the CA form compared to the SU form suggested in our results adds another difference between these forms, currently under study to determine whether they are different species. This study is the first on mating systems in funnel-web wolf spiders, adding knowledge to the discussion about the evolution of sexual strategies in this group.

Are multiple copulations harmful? Damage to male pedipalps in the funnel-web wolf spider Aglaoctenus lagotis (Araneae: Lycosidae)

Damage to genital structures during copulation has been reported in about twenty spider families, but never in Lycosidae. Aglaoctenus lagotis (Holmberg, 1876), a South American wolf spider, is one of the few that live their whole lives in funnel-webs. This work reports on the damage to pedipalpal bulbs observed in males of the “southern Uruguay” form of A. lagotis with multiple copulations. Observed damage consists of the irreversible expansion of the hematodocha and even its explosion. A high copulation cost resulting from multiple and long-lasting copulations could be causing this damage, affecting the mechanism of sperm transference in a definitive way. This is the first report of pedipalp damage in lycosids, and also the first report of damage involving the hematodocha in spiders.

Funnel-web construction and estimated immune costs in Aglaoctenus lagotis (Araneae: Lycosidae)

Abstract Constructing webs for survival is rare in wolf spiders. However, some species, postulated as basal in the family, live in funnel-webs. Aglaoctenus lagotis (Holmberg 1876), a South American lycosid, lives permanently in webs. It is virtually unknown how web construction occurs for this species and the few other lycosid weavers. Also, costs associated with construction have not been studied, although funnels are suggested to be particularly costly webs. This study describes the funnel-web construction behavior of A. lagotis (Lycosidae: Sosippinae) and measures its costs in subadult and adult individuals. We recorded web construction, effects of sealing spinnerets in weaving activity, and immune costs of weaving (measuring melanization of an implant) in individuals allowed to weave and prevented from weaving. Construction consisted of three alternating behaviors: deposition of thick threads with a radial orientation and prolonged attachments (mainly involving the anterior spinnerets); deposition of ...

Funnel-web construction and estimated immune costs inAglaoctenus lagotis(Araneae: Lycosidae)

Constructing webs for survival is rare in wolf spiders. However, some species, postulated as basal in the family, live in funnel-webs. Aglaoctenus lagotis (Holmberg 1876), a South American lycosid, lives permanently in webs. It is virtually unknown how web construction occurs for this species and the few other lycosid weavers. Also, costs associated with construction have not been studied, although funnels are suggested to be particularly costly webs. This study describes the funnel-web construction behavior of A. lagotis (Lycosidae: Sosippinae) and measures its costs in subadult and adult individuals. We recorded web construction, effects of sealing spinnerets in weaving activity, and immune costs of weaving (measuring melanization of an implant) in individuals allowed to weave and prevented from weaving. Construction consisted of three alternating behaviors: deposition of thick threads with a radial orientation and prolonged attachments (mainly involving the anterior spinnerets); deposition of swaths of fine threads without consistent orientation and with short attachments (mainly involving the posterior spinnerets); and motionlessness. No sticky threads are present in the web. The thick threads have a supporting function and the fine threads have a filling function. Subadults and males allowed to weave reduced their immune response compared with those prevented from weaving; no such relationship was observed for females. Males presented the weakest immune response, followed by subadults and females. The web construction process showed greater similarity with agelenid spiders than with the only other lycosid studied, Sosippus janus Brady 1972, and appears to be a costly activity, especially for males.

Reproductive isolation between two populations ofAglaoctenus lagotis, a funnel-web wolf spider

Aglaoctenus lagotis (Lycosidae: Sosippinae) is a spider that, in contrast to the predominant wandering habit of the family, constructs funnel webs. The species is widely distributed throughout the Neotropics and is credited with high levels of intraspecific variation. Here, we evaluate whether reproductive isolating barriers operate between some populations of A. lagotis. We used heterotypic encounters between individuals from two distant localities: southern Uruguay (SU) and Central Argentina (CA). Additionally, we used spiders from an intermediate locality, western Uruguay (WU), where both forms of the species overlap (SU.WU was used to describe individuals from WU reminiscent of those from SU; and CA.WU was used to describe individuals from WU reminiscent of those from CA). No copulations occurred between SU and CA individuals, whereas a single and atypical copulation occurred between SU.WU and CA.WU individuals. Attacks (only by females on males) were rare. In tests of choice based on silk cues, SU males did not prefer homotypic cues but almost did not court CA females, whereas CA males preferred homotypic cues but usually courted heterotypic females. These findings, with a previously reported temporal asynchrony between populations, suggest the occurrence of reproductive isolation between both spider forms and a speciation process favoured by the wide distribution and plasticity of the species. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 646–658.

Cryptic diversity of Aglaoctenus lagotis (Araneae, Lycosidae) in the Brazilian Atlantic Rainforest: evidence from microsatellite and mitochondrial DNA sequence data

Tropical spiders have been poorly studied, and studies regarding the distribution of genetic diversity in natural populations of these species are even more scarce. Among the spider genera, the South American genus Aglaoctenus includes species that build tube-shaped webs and display subsocial behavior that includes parental care. Herein we studied the population genetics of Aglaoctenus lagotis in five primary fragments of the Brazilian Atlantic Forest (with varying distances between 2 and 47 km) considered a conservation hotspot. In this study, we used two molecular markers: microsatellites and the COI mitochondrial gene. The data obtained indicated the presence of two genetic lineages (A and B), as evidenced by both markers, suggesting the presence of cryptic diversity. Lineages subpopulations are not completely isolated and have moderate structure (FST A=0.118; FST B= 0.142). Dispersal by air (or ballooning) must occur and possibly allows the maintenance of gene flow between sample sites. The hypotheses that lineages found here represent distinct species cannot be confirmed until further studies have been carried out. However, regardless of its taxonomic classification, the genetic lineages, found here, should be considered as individual units in future evolutionary studies of this species.

The effects of forest fragmentation on the population ecology and natural history of a funnel-web spider

Habitat fragmentation strongly affects the abundance, distribution, body size and population genetics of invertebrates. Urban growth in Brazil has led to severe fragmentation, especially in the Atlantic Forest and savannas. The effects of this fragmentation on the common funnel-web spider Aglaoctenus lagotis were examined in two forest fragments within the interior savanna: a smaller fragment within an urban environment and a larger fragment within a rural environment. The reproductive period occurred in October, coinciding with the beginning of the rainy season, when the species was aggregated in the two forest fragments. The smaller fragment contained a larger population, and the spiders had a larger average prosoma size and web area. The presence of a larger population in a smaller area within the urban centre may reflect a limited dispersal ability, reduced predator abundance or low interspecific competition. The larger prosoma length and web area in the smaller habitat fragment suggest greater resource availability and a higher probability of capturing prey in the urban environment. In both areas, a larger number of capture threads was positively correlated with the presence of inquiline spiders in the webs. The genetic data indicate close similarity between and within the two areas, indicating that the species has low genetic variability or that the areas studied, consistent with their proximity, have separated only recently. Most savannas and forests in midwestern Brazil have recently undergone severe fragmentation, and further studies of this nature are needed.

Strong phenological differences between two populations of a Neotropical funnel-web wolf spider

Comparisons of phenological patterns among populations within a species are uncommon in arachnids. Aglaoctenus lagotis is a wolf spider that lives in funnel-webs across South America. The aim of this study was to describe the phenological patterns of two distant populations of A. lagotis (central Argentina, CA, and southern Uruguay, SU). Individuals of each population were sighted along transects, every month for two years. The CA and SU populations differed in their phenological patterns (Wald χ2 = 966.94, df = 66; p <0.001). The CA population showed a spring–summer unified reproductive season and immature individuals overwintered. SU showed the sexual period during autumn, the maternal period during spring–summer and the females, mostly mated, overwintered. These strong differences imply temporal isolation in mating possibilities between both populations. The differences encountered could be due to phenotypic plasticity or have a phylogenetic basis. Interpopulation studies of other features of A. lagotis would show whether they also vary, suggesting speciation.

Differences in sexual behavior of two distant populations of the funnel-web wolf spider Aglaoctenus lagotis

Generally, sexual repertoire within a species is conserved, but frequencies of occurrence of sexual behavioral acts often vary, and wide geographic distributions may favor these variations. Aglaoctenus lagotis is distributed along South America and belongs to Sosippinae, a subfamily of wolf spiders that builds funnel webs. Previous reports, based on different populations, suggested variations in sexual behavior and life cycle. Our objective was to describe and compare the sexual behavior of two populations of A. lagotis: ‘Southern Uruguay’ (SU) and ‘Central Argentina’ (CA). We carried out intrapopulation trials, in the laboratory, with 15 female–male pair matings. The most representative courtship acts in SU were web-stretching, striding-forward and forelegs-elevating, whereas in CA they were alternate-waving, web-stretching and leg-tapping. Juddering, forelegs-elevating and striding-forward were exclusive for SU, while alternate-waving and simultaneous-waving were exclusive for CA. We also found differences in copulatory characteristics such as frequencies of insertions and ejaculations. We documented body-shaking during copulation for the first time. Some sexual acts were exclusive of each population, while the shared ones differed in pattern and frequencies of occurrence. In addition to variations in sexual periods, these differences may favor divergence processes or an exceptional high level of flexibility in the sexual behavior of A. lagotis.

Oviposition and post-embryonic development of Aglaoctenus lagotis (Araneae: Lycosidae)

The present study describes the life history of Aglaoctenus lagotis Holmberg, 1876 from oviposition to adulthood, analyzing the number of eggs in each egg sac, birth rate, number of instars, sex ratio, cephalothorax size of all instars, and developmental time in laboratory. The results indicate that the studied species can produce two egg sacs during the reproductive period, and that the post-embryonic phase includes 12 nymphal instars. A higher mortality rate was observed during the first three instars, featuring a Type III survival curve. The sex ratio was geared towards the female in the adults and no significant difference was observed in the length of the cephalothorax between male and female. This species can therefore be considered monomorphic. Sexual dimorphism was observed in the cuticle color, with males being light brown whereas females are dark brown.

Mating behaviour and maternal care in the tropical savanna funnel-web spider Aglaoctenus lagotis Holmberg (Araneae: Lycosidae)

Despite their abundance and diversity, Neotropical spiders have been the subject of relatively few studies of behavioural ecology. The sexual behaviour and maternal care of the spider Aglaoctenus lagotis (Lycosidae) is described here. We performed experimental manipulations to test the hypothesis that males are attracted by female cues in the web. Two predictions were tested: (a) webs used by a virgin female will attract more males than webs used by an inseminated female; (b) the main cue in the web is chemical, so webs recently used by virgin females will attract more males than those that are not recently used. Additionally, we tested the hypothesis that maternal care increases offspring survivorship. Results showed that males are attracted by recently used webs (z = 0.0015; p = 0.037; z-test) and webs of virgin females (z = 0.041; p = 0.036, z-test). Male sexual behaviour presented three different categories: court, pre-mate and mate. After the mating, the females built a cocoon that was transported adhered to the spinnerets and held by the last pair of legs. After the hatching of the eggs, the young migrated to the dorsal region of the mother's body for 5 days. During maternal care the mother eliminates a yellowish drop from its oral cavity, which is collected by the young. During the development of the young until adulthood, the offspring that have their mother present in the first stages of life have greater survival compared with those without maternal care. Our results make it possible to perform comparative analyses between a South American Lycosidae species and other species distributed worldwide.

A revision of the Neotropical nursery-web spider genus Architis (Araneae: Pisauridae)

The spider genus Architis Simon, 1898 is revised, resulting in sixteen species distributed from Panama to southern Brazil, all herein diagnosed, described and illustrated. Pisaurina brasiliensis Mello-Leitão, 1940 is transferred to Architis and considered a senior synonym of A. sinops Carico, 1989. The females of A. capricorna Carico, 1981 and A. robusta Carico, 1981 are described and illustrated for the first time. Architis nitidopilosa Simon, 1898 is considered a junior synonym of A. tenuis Simon, 1898 (the type species of the genus) and A. suarez Carico, 1989 a junior synonym of A. cymatilis Carico, 1981. The remaining species, A. ikuruwa Carico, 1981; A. tenuipes (Simon, 1898) and A. helveola (Simon, 1898) are redescribed and illustrated. Architis paulistana Mello-Leitão, 1917 is synonymised with Aglaoctenus lagotis (Holmberg, 1876) (Lycosidae: Sosippinae) based on its original description and type locality. Eight new species are described: A. erwini sp. nov., based on male and female specimens from Ecuador; A. comaina sp. nov. (male and female) and A. dianasilvae sp. nov. (female only) from Peru; A. maturaca sp. nov. (male and female) and A. altamira sp. nov. (female only) from Brazilian Amazonia; A. colombo sp. nov. (male and female), A. fritzmuelleri sp. nov. (female only) and A. turvo sp. nov. (female only) from southern and southeastern Brazil.