Effects of sexual dimorphism and body size on feeding behaviour of the fiddler crab, Uca bengali Crane, 1975

Crustaceana ◽  
2015 ◽  
Vol 88 (2) ◽  
pp. 231-242 ◽  
Author(s):  
F. W. Tina ◽  
M. Jaroensutasinee ◽  
K. Jaroensutasinee

Uca bengaliCrane, 1975 females have two small feeding claws but males have one small feeding claw and another big claw used for waving and fights. On the basis of video recordings of feeding motions and duration, and morphometric measurements of body size (measured as carapace width) and feeding claw size (measured as dactyl length and width), differences in feeding rate per crab and per feeding claw, feeding duration, and feeding claw size between sexes were studied with the main aim to test male ability to compensate for the loss of one functional feeding claw. Additionally, feeding rate of males and females of small and large size classes was studied. Furthermore, correlations between feeding rate and body size, as well as feeding claw size and body size were investigated. Results showed that increased feeding rate per feeding claw coupled with a larger feeding claw allowed males to compensate for the loss of one feeding claw. Smaller males and females fed faster than larger ones. There was a negative correlation between feeding rate and carapace width. Feeding duration did not vary between males and females of comparable size. A positive correlation was observed between feeding claw size and carapace width.

Author(s):  
Gustavo Luis Hirose ◽  
Vivian Fransozo ◽  
Carolina Tropea ◽  
Laura S. López-Greco ◽  
Maria Lucia Negreiros-Fransozo

Some crustaceans show variations of their reproductive biology within their geographical distribution, and knowledge about such variations is important for the comprehension of their reproductive adaptations. This study compared two populations of the fiddler crab Uca uruguayensis from two locations on the south-western Atlantic coast: Ubatuba Bay, São Paulo, Brazil and Samborombón Bay, Buenos Aires, Argentina. The population features analysed were the body size variation (carapace width = CW) and the size at the onset of sexual maturity (SOM) in order to test the hypothesis that the size at SOM, should be the same in relative terms (RSOM), independently of the latitudinal position. In the Brazilian population the CW ranged from 4.18 to 11.60 mm for males and 3.90 to 9.80 mm for females, and in the Argentinean population from 3.60 to 14.10 mm for males and 2.85 to 12.00 mm for females. In the Brazilian population the SOM was 7.1 (RSOM = 0.58) and 5.9 mm CW (RSOM = 0.57) for males and females, respectively, and in the Argentinean population it was 7.0 (RSOM = 0.42) and 6.75 mm CW (RSOM = 0.53) for males and females, respectively. This fact is probably related to a great plasticity in the life history features of Uca uruguayensis under different environmental conditions.


Behaviour ◽  
2018 ◽  
Vol 155 (10-12) ◽  
pp. 905-914 ◽  
Author(s):  
Fahmida W. Tina ◽  
M. Jaroensutasinee ◽  
K. Jaroensutasinee

Abstract We tested for the first time how Austruca bengali Crane, 1975 signaller males adjusted their waving rates based on receiver female body sizes and their distances. We video recorded the waving display of 46 males (9–12 mm carapace width) for 30 s, and counted their waving rate. Receiver females were categorised as small (8–10 mm carapace width) and large (>10 mm). Distances between males and females were categorised as short (⩽12 cm) and long (>12 cm) distances. Our results indicate that males are able to measure distances and female sizes, and adjust their waving display by actively reducing waving rate (1) towards small females, as usually small females have lower fecundity compared to large ones and (2) towards females at very close distance because at this point, the females would make their mating decision, and thus males start to lead/hit the females towards their burrow rather than waving vigorously.


Crustaceana ◽  
2015 ◽  
Vol 88 (12-14) ◽  
pp. 1283-1299 ◽  
Author(s):  
Fahmida Wazed Tina ◽  
Mullica Jaroensutasinee ◽  
Krisanadej Jaroensutasinee

We examined the effects of population density on body size and burrow characteristics ofUca bengaliCrane, 1975. We predicted that (1) males in high-density areas (HD) should be larger in size and build higher quality burrows than males in low-density areas (LD), and (2) HD females should be larger in size, but build lower quality burrows than LD females, as HD females can find higher numbers of good quality male burrows around them for breeding and egg incubation. Our results showed that males and females in HD were larger in size than those in LD. Since HD males were larger in size, they built higher quality burrows than males in LD. On the other hand, even though LD females were smaller in size than HD ones, they built higher quality burrows than HD females. Our results thus indicate that density effects both body size and burrow characteristics.


2021 ◽  
Vol 14 ◽  
Author(s):  
Sami Badwan ◽  
James Harper

Background: A relationship between body size and longevity has long been appreciated within eukaryotes, especially vertebrates. Introduction: In general, large size is associated with increased longevity among species of mammals and birds but is associated with decreased longevity within individual species such as dogs and mice. In this study, we examined the relationship between measures of individual body size and longevity in a captive population of speckled cockroaches (Nauphoeta cineria). Method: Newly molted adults of both sexes were removed from a mass colony housed in multiple terraria and housed individually with food and water provided ad libitum for the duration of their lifespan. Thrice weekly, the status (i.e. live/dead) of individual cockroaches was noted for the duration of the study. Individuals found dead were weighed and measured to obtain body mass and morphometric measures and the age at the time of death was recorded. The relationship between body size and lifespan was assessed. Result: Contrary to what is commonly seen within vertebrates, large cockroaches were longer-lived than their smaller counterparts. Specifically, body mass, body length and pronotum width were all significantly correlated with the age at death in a mixed population of males and females (n = 94). In addition, we found that the longevity of a historically larger population in terms of both body mass and body length were significantly longer-lived than the population used in this study. Conclusion: These data indicate there is a significant interaction between body size and aging in this species and that increased size results in a survival advantage. There is evidence in the literature indicating that a positive relationship between size and longevity may be common in insects.


Behaviour ◽  
2017 ◽  
Vol 154 (7-8) ◽  
pp. 741-764 ◽  
Author(s):  
Eilea R. Knotts

Recognizing which phenotypic traits are predictors for habitat choice can have important implications for understanding population dynamics. This study determined whether body size, sex, activity level, or origin habitat affected the preference of the fiddler crab,Uca pugilator, in selecting either a marsh or open mudflat, two habitats differing in risk level and food availability. Combining field and laboratory experiments, this study indicated a significant difference in body size and activity level of crabs between habitats. Further investigation of phenotypic dependency on habitat preference resulted in interactions between origin habitat and carapace width and activity level. When split by origin habitat, habitat preference for the open mudflat was predicted by body size for crabs originating from the open mudflat and by activity level for the crabs originating from theSpartinamarsh. These results suggest that, forU. pugilator, body size plays a large role in the preference for exposed habitat.


2009 ◽  
Vol 31 (73/75) ◽  
Author(s):  
Vivian Fransozo ◽  
Rafael Campanelli Mortari ◽  
Aline Staskowian Benetti

The population biology of the fiddler crab Uca mordax (Smith, 1870) was investigated in an estuarinemangrove from the southeastern coast of Brazil. Samplings were monthly performed by 2 collectors for30 min. using the technique of capture per unit effort during low tide periods. The allometric techniquewas used to determine crab size at sexual maturity (males and females). Thus, specimens were classified into juveniles and adults according to their size at sexual maturity for each sex. The specimens weredistributed into size classes. Recruitment was based on the juvenile frequency and the reproduction peakin ovigerous females. The median size of males was 15.9 ± 2.7 mm carapace width (CW) (n = 557) andthat of females, 14.6 ± 2.8 mm CW (n = 528). At sexual maturity, size of crabs was 11.9 mm CW formales and 11.5 mm CW for females. Juveniles were found throughout the year but more frequently inthe winter and autumn. Sex ratio did not differ among seasons, except during the summer (p < 0.05).As regards sex ratio per size class, females predominated in the fi rst size classes. Reproduction peakwas observed in the summer. In short, the population biology of U. mordax was similar to that of mostbroad-front fi ddler crab species.


Crustaceana ◽  
2017 ◽  
Vol 90 (6) ◽  
pp. 735-743 ◽  
Author(s):  
Fahmida Wazed Tina ◽  
Mullica Jaroensutasinee ◽  
Krisanadej Jaroensutasinee

We video-recorded and examined the burrow building behaviour of small and large males and females ofUca annulipes(H. Milne Edwards, 1837). Males took a longer time than females, and larger crabs took a longer time than smaller ones, to build burrows. Higher numbers of mudballs were excavated from inside the burrows during the build of the burrows by males than by females, and by larger crabs than by smaller ones. Crab carapace width was positively correlated with the time required to build burrows, and with the number of mudballs excavated from inside the burrows during the build of these burrows. We observed that 82% of the females placed the mudballs near their burrow entrance, whereas 85% of the males placed the mudballs far from their burrow entrance. After building the burrows, 71% of the females went inside the burrow and plugged the burrow entrance, and 90% of the males foraged for food.


1970 ◽  
Vol 27 (9) ◽  
pp. 1607-1616 ◽  
Author(s):  
J. Watson

Morphometric measurements and gonad examination of the spider crab, Chionoecetes opilio, showed that 50% maturity occurred at about 57 and 50 mm carapace width for males and females, with minimum sizes at maturity of 51 (males) and 47 mm (females). Both sexes were mature at sizes considerably below the commercially acceptable size of 4 inches (102 mm) carapace width. After maturity, positive allometric growth was demonstrated for males. Females do not moult after reaching maturity. The small vasa deferentia found in soft-shelled mature males suggested that only hard-shelled males were capable of mating. A hard-shelled male successfully mated with a soft-shelled mature female. Field and laboratory observations suggest that more than one brood is commonly produced from one mating.The minimum size limit for commercial landings allows some mature males capable of mating to be left on the fishing grounds. Retention of this limit seems unlikely to affect the breeding potential of the population.


2006 ◽  
Vol 49 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Daniela da Silva Castiglioni ◽  
Maria Lucia Negreiros-Fransozo

The gonad development of Uca rapax was studied to achieve the size at onset of its sexual maturity. Crabs were sampled from April/2001 to March/2002 in the Itamambuca and Ubatumirim mangroves in Ubatuba, São Paulo, Brazil. The specimens were grouped in 10 size classes. Juveniles and adult crabs frequencies were assessed for each class. The size of carapace width in which 50% of males and females were considered mature was 14.8 and 12.1 mm (Itamambuca) and 13.6 and 11.4 mm (Ubatumirim), respectively for males and females. Males matured at higher sizes than females, probably due to a major investment in their somatic growth, while females spend their energy in the reproductive process, saving energy for eggs' production.


2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.


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