Results of the present study show that the level of allometry of male chelae does not change abruptly at pubertal moult and therefore immature and mature crabs cannot be distinguished on this basis. This replicats the findings of Sumpton (1990b) for Charybdis natator, in which he did not find any evidence of discontinuities in the relative growth of male chelae.
It is however well documented for portunid crabs that the level of allometry of male chelae does change suddenly at the pubertal moult in such species as Scylla serrata (Knuckey, 1996; Imtiaz et al., 1998), S. olivacea and S. paramamosain (Overton and Macintosh, 2002), Portunus pelagicus (Shields and Wood, 1993), P. sanguinolentus (Rasheed and Mustaquim, 2010), Liocarcinus depurator (Muino et al., 1999), Ovalipes stephensoni (Haefner, 1985), and Charybdis bimaculata (Doi et al., 2008) and the immature and mature crabs can be distiguished on the basis of phase allometry.
Chelae, in sexualy dimorphic crabs, are used by males in terretorial defence, combat, display and carrying female during courtship (Hartnoll, 1982). The level of allometry of male chelae is slightly higher than the females in juvenile phase and a large increase in the level of phase allometry at the pubetal moult brings the male chelae to full functional size at sexual maturity (Hartnoll. 1982). Where there is little sexual dimorphism, the role of chelae can be correlated with behaviour patterns. Hartnoll (1982) mentions the example of Goniopsis cruentata, a barchyuran crab of family Grapsidae, where dimorphism is little and both sexes play equal role in display and combat.
The chelae of Charybdis feriatus show little sexual dimorphisms and both sexes may play equal role in display and combat. Hence no ...
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...n the present study was found to vary from 1,270,399 to 3,774,114 and is higher than those reported earlier. Padayatti (1990) from Cochin, India reported 52,350 to 309,250 eggs while Rameshbabu et al. (2006) found fecundity to vary from 35,635 to 349,939. However studies involving spawning and larval rearing in captivity have shown higher number of eggs and / or zoea produced by female C. feriatus. Parado-Estepa et al (2002) from Philippines and Josileen (2011) from India have reported that a female C. feriatus can produce 1,200,000 and 1,400,000 zoea, respectively. The higher number of egg found in the present study may be attributed to the methodology. Only those females were used which had recently spawned eggs (bright orange) on their abdomen rather than crabs having eyed-stage egg (grey colour), for some eggs are lost during incubation and / or during handling.
Because of its size and abundance, T. californicus is commonly regarded as the insect of the sea. This creature is generally very small, from 1-3 mm in size as adults. They are cylindrically shaped, and have a segmented body (head, thorax, abdomen) though no noticeable division between body regions (Powlik 1966). Each segment of the body has a pair of legs. They use their 'legs' to propel themselves through the water in short rapid jerks. They have 2 pairs of long feathered antennae, a chitin us exoskeleton and a single eye in the middle of their head, this simple eye can only differentiate between light and dark.
A lobster must shed its shell in order to grow. It takes about five to seven years for a lobster to become a legal size harvestable adult. Soft-shell is the term used for a newly molted lobster. A soft-shell lobster has a shell with room for growth. Soft-shell lobsters are not as full of meat because their new shell is larger than the muscle inside the body. The part not filled with its body’s muscle tissue is filled with water. Soft-shell lobsters may look big on the outside, but they have a much lower meat yield on the inside. Most adult lobsters molt from June to September depending upon location and water temperatures.
In his peer-reviewed article, “Sexing fossils: a boy named Lucy?,” James Shreeve discusses, in detail, a study on sexual dimorphism and possible speciation in Australopithecines in Hadar, Ethiopia, based on the famous A. afarensis specimen, “Lucy.” In the article, “Lucy’s kind takes humanlike turn,” the author addresses sexual dimorphism and speculates on sex-based differences in behaviors in A. afarensis. The two articles have differences and commonalities with each other in content and both present research methods and conclusions on topics including sexual dimorphism, sex-based behaviors, and speciation in Australopithecines, which receive critical analysis.
Judge, K.A., and Bonanno, V.L. 2008. Male weaponry in a fighting cricket. PLoS ONE 3:e3980.
The yeti crab is a very recent discovery. Nothing is known about its reproduction habits, due to its place of living.
The picture above shows the vast difference that there can be in animals, to the right is Emerita Analoga (sand crab), and to the left is Zalophus Californianus (California Sea Lion). The sand crab is an invertebrate while the seal is a vertebrate and mammal. Invertebrates make up 90% of all an...
The location is one of the most critical factors to analyze thoroughly because it helps predict whether the sales of the choosing location will be good or not? Although the Boiling Crab is in the growth stage, it still has to focus on new locations that the owner plan to extend to these areas. As I mentioned in the introduction, the owner plans to open the Boiling Crab in four new locations soon.
The North American brine shrimp goes through several stages in development before reaching adulthood. The brine shrimp is first encased in a protective capsule within a female brine shrimp’s brood sac (Drewes, C, 2006). Here, egg development rapidly...
Three spined stickle back fishes are small fishes with a deep body with three spines in front of the dorsal fin and are therefore are named stickle back because if the spines on the dorsal fin. These fishes are brownish, green and pale or orange reddish on the underside and are about 6 cm in length. The breeding male fish usually has a red belly and blue eyes. The three spined stickleback fishes are found in Northern Asia, northern America and Europe and some parts of southern and central Europe such as Belgium. These fishes take about three years in breeding and they normally breed between late March and early August. Many populations of three spined sticklebacks take two years to mature and because of this they have one breeding season before dying.
to the lobster and crab. Their closest living relative today is the horseshoe crab.The name
To start off, the horseshoe crab lived 200 million years before dinosaurs. What’s astounding is that while dinosaurs have become extinct, the horseshoe crab is still alive and well today (Horseshoe Crab:Saint Louis Zoo). Next is that it might not seem like it, but this critter is actually a predator. The crab likes to feed on things such as small clams, crustaceans, worms, algae, and other animals (Steel). Furthermore this animal is also known as the king crab. Finally the male horseshoe crab is actually shorter than the female the crab. The male is about 14-15 inches long from head to tail, while the female is measures in to be 18-19 inches long (Horseshoe Crab
The platypus is sexually dimorphic in that males of the species are larger in size than females. Size variation within populations from different regions is also evident, with smaller platypuses in general being found in north Queensland compared to Tasmania. Additionally, each male bears a horny spur on the ankle of the hind leg reaching roughly 1.5 cm in length. This spur is connected to a venom glad and is used to fight for females and ensures spatial separation.
Soft corals are very widespread among the Great Barrier Reef and other Indo-Pacific coral reefs. On the Great Barrier Reef they may cover up to 37% of the reef area (Bastidas, et. al, 2001). Even though soft corals are abundant on the Great Barrier Reef they have been overshadowed by the study of hard corals. Very little research has been conducted on them, yet they are just as fascinating as their hard coral neighbors. The main purpose of this paper is to explain why evolution has made it possible for soft corals to reproduce both sexually and asexually. To do this I will first introduce soft corals, then explain the types of reproduction soft corals are capable of, and finally explain why evolution has made it possible for soft corals to reproduce both sexually and asexually, using numerous studies to support my claims. Most of the information on this topic was very species specific, but this paper will explain the reproductive evolution of soft corals in a broader array that will pertain to the scientific order Alcyonacea, or all types of soft corals.
Behavioural hypothesis centres on protection of nest and the forming of the mating bond. (Mueller (1990) p. 553-585). This has similarities with the male mating theory.