Reproductive isolation and sex-role reversal in two sympatric sand-dwelling wolf spiders of the genus Allocosa

2008 ◽  
Vol 86 (7) ◽  
pp. 648-658 ◽  
Author(s):  
A. Aisenberg ◽  
F. G. Costa
Keyword(s):  
Reproductive Isolation ◽  
Sexual Size Dimorphism ◽  
Sex Role ◽  
Wolf Spider ◽  
Coastal Dunes ◽  
Pitfall Trap ◽  
Role Reversal ◽  
Adult Size ◽  
Wolf Spiders ◽  
Size Dimorphism

Allocosa brasiliensis (Petrunkevitch, 1910) is a nocturnal wolf spider inhabitant of coastal dunes. Pitfall-trap data suggested the occurrence of two sympatric and synchronic morphs, with differences in adult size and abdominal design (minor and major morphs). Previous studies performed with the major morph of A. brasiliensis, postulated courtship-role and sexual size dimorphism reversal for this spider. In the present study, we compare data on development and morphology and test reproductive isolation between morphs of A. brasiliensis, with the hypotheses that the two morphs are reproductively isolated and both show courtship-role reversal. As had been reported for the major morph of A. brasiliensis, the minor-morph females approached the burrows of minor-morph males, entered, initiated courtship, and after copulation, males closed their burrows with female cooperation from the inside. Females did not court or copulate with males belonging to the other morph and, in two cases, major-morph females cannibalised minor-morph males. Morphometrical and developmental data showed differences between morphs. The occurrence of copulation only between individuals of the same morph confirm reproductive isolation, supporting the occurrence of two species. Morphological and behavioural data are consistent with courtship-role-reversal hypotheses for the minor morph, constituting the second report in spiders of this atypical behaviour.

scholarly journals Climate change and sexual size dimorphism in an Arctic spider

2009 ◽  
Vol 5 (4) ◽  
pp. 542-544 ◽  
Author(s):  
Toke Thomas Høye ◽  
Jörg U. Hammel ◽  
Thomas Fuchs ◽  
Søren Toft
Keyword(s):  
Climate Change ◽  
Sexual Size Dimorphism ◽  
Carapace Width ◽  
Wolf Spider ◽  
High Arctic ◽  
Relative Fitness ◽  
Size Dimorphism ◽  
Adult Body ◽  
Body Sizes ◽  
Female Responses

Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider Pardosa glacialis from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. Earlier snowmelt during both years of its biennial maturation resulted in larger adult body sizes and a skew towards positive sexual size dimorphism (females bigger than males). These results illustrate the pervasive influence of climate on key life-history traits and indicate that male and female responses to climate should be investigated separately whenever possible.

Sexual dimorphism in chelicerae, forelegs and palpal traits in two burrowing wolf spiders (Araneae: Lycosidae) with sex-role reversal

2010 ◽  
Vol 44 (19-20) ◽  
pp. 1189-1202 ◽  
Author(s):  
A. Aisenberg ◽  
F.G. Costa ◽  
M. González ◽  
R. Postiglioni ◽  
F. Pérez-Miles
Keyword(s):  
Sexual Dimorphism ◽  
Sex Role ◽  
Role Reversal ◽  
Wolf Spiders ◽  
Sex Role Reversal

scholarly journals Male sexual cannibalism in a sand-dwelling wolf spider with sex role reversal

2011 ◽  
Vol 103 (1) ◽  
pp. 68-75 ◽  
Author(s):  
ANITA AISENBERG ◽  
FERNANDO G. COSTA ◽  
MACARENA GONZÁLEZ
Keyword(s):  
Sex Role ◽  
Wolf Spider ◽  
Role Reversal ◽  
Sexual Cannibalism ◽  
Sex Role Reversal

Growth and sexual size dimorphism in Alberta populations of the eastern short-horned lizard, Phrynosoma douglassi brevirostre

1985 ◽  
Vol 63 (1) ◽  
pp. 139-154 ◽  
Author(s):  
G. Lawrence Powell ◽  
Anthony P. Russell
Keyword(s):  
Growth Model ◽  
Sexual Difference ◽  
Sexual Size Dimorphism ◽  
Growth Models ◽  
Tail Length ◽  
Growth Patterns ◽  
Head Width ◽  
Adult Size ◽  
Adult Males ◽  
Size Dimorphism

Alberta populations of Phrynosoma douglassi brevirostre display marked sexual size dimorphism, adult females being considerably larger than adult males. Discriminant analyses of whole mensural characters and of scaled mensural characters indicate that this dimorphism is present from birth, although it is more strongly expressed after sexual maturity. Recapture data were used to generate modified logistic by weight growth models for snout–vent length (SVL), and allometric models for each sex were generated for growth in tail length, head length, and head width. The SVL growth model for females indicates delayed maturity leading to greater adult size, an expected feature of a female viviparine. The SVL growth model for males indicates that growth ceases sooner than in females, resulting in a smaller adult size. This is possibly a result of male dispersal competition, an hypothesis further borne out by the results of a preliminary analysis of mobility in the two sexes, and may also be influenced by intersexual dietary competition. Differences in head dimensions between the sexes are a function of the differences in SVL at adulthood, but there is a significant sexual difference in the allometric relationship of tail length to SVL. No difference in the growth patterns and adult size of either sex was found to exist over the range in Alberta.

Reversed Sexual Size Dimorphism and Parental Care: Minimal Division of Labour in the Blue-Footed Booby

Behaviour ◽  
1995 ◽  
Vol 132 (7-8) ◽  
pp. 479-496 ◽  
Author(s):  
Hugh Drummond ◽  
Maria Guerra
Keyword(s):  
Parental Care ◽  
Sexual Size Dimorphism ◽  
Division Of Labour ◽  
Avian Species ◽  
Nest Defence ◽  
Adult Size ◽  
Size Dimorphism ◽  
Behavioural Observation ◽  
Males And Females ◽  
Reversed Sexual Size Dimorphism

AbstractReversed sexual size dimorphism in avian species (females larger than males) may be an adaptive consequence of different roles of males and females in parental care. We examined the alleged division of labour in two-chick broods of the blue-footed booby, using behavioural observation and frequent weighing of chicks. In the first week of parental care, males and females fed broods at similar frequencies and provided similar masses of food, but females brooded more than males when broods were 5-10 d old. Subsequently, females provided a greater mass of food and frequency of feeds than males until chicks were at least 35 d old (mass) and 60 d old (frequency), while attending the brood for just as much time as males until chicks were at least 35 d old. Males and females did not differ in the tendency to feed (frequency and mass) the first-hatched chick differentially. In nearly all components of parental care examined here, and in other studies, the female's contribution is equal to or greater than the male's. Only in clutch attendance and nest defence does the male contribute more than the female, but his small size seems unlikely to enhance performance in these activities. Overall, small size appears potentially to limit male provisioning of the brood, and is unlikely to be an adaptation for division oflabour in parental care. This result casts doubt on the relevance of the division-of-labour hypothesis for adult size dimorphism.

scholarly journals Modest sexual size dimorphism and allometric growth: a study based on growth and gonad development in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae)

Biology Open ◽  
2021 ◽  
Vol 10 (12) ◽  
Author(s):  
Fan Zhang ◽  
Xiaoqiong Chen ◽  
Chi Zeng ◽  
Lelei Wen ◽  
Yao Zhao ◽  
...  
Keyword(s):  
Sexual Size Dimorphism ◽  
Specific Growth ◽  
Gonad Development ◽  
Wolf Spider ◽  
Growth Strategies ◽  
Allometric Growth ◽  
Developmental Duration ◽  
Potential Growth ◽  
Size Dimorphism ◽  
Pardosa Pseudoannulata

ABSTRACT Sexual size dimorphism (SSD) is a notable phenomenon in terrestrial animals, and it is correlated with unusual morphological traits. To date, the underlying sex-specific growth strategies throughout the ontogenetic stage of spiders are poorly understood. Here, we comprehensively investigated how the growth trajectories and gonad development shaped SSD in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae). We also hypothesized the potential growth allometry among the carapace, abdomen, and gonads of spiders in both sexes. By measuring the size of the carapace and abdomen, investigating developmental duration and growth rate, describing the gonadal sections, and calculating the area of gonads at all instars from hatching to maturity, we demonstrated that SSD results from sex-specific growth strategies. Our results indicated that the growth and developmental differences between both sexes appeared at early life stages, and there was allometric growth in the carapace, abdomen, and gonads between males and females.

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