Search

1. 1. The aggressive communication system of the mantis shrimp Gonodactylus bredini was studied. The data from 1-hr observation periods involving interactions between homosexual pairs were used to analyse the distribution of acts within individuals and the distribution of acts by one animal following the execution of a particular display by the other animal. 2. 2. When distributions following particular acts were compared with the overall distribution of patterns, most were found to be significantly different. This indicates that particular sequences of behaviour were likely to occur. In the case of inter-individual sequences most behaviour patterns elicited a specific change in the behaviour of a recipient animal; communication was thus taking place. 3. 3. The frequency with which aggressive interactions took place decreased with time. There were also changes in the overall distributions of the various acts. Both these changes occurred concurrently with the establishment of a dominant-subordinate relationship. 4. 4. In the inter-individual sequences specific acts were statistically ‘directive’ or ‘inhibitive’ toward other acts. Changes in the acts toward which these were directive or inhibitive also occurred over time and were correlated with the formation of a dominant-subordinate relationship. The establishment of such a relationship, therefore, seems to involve at least partially changes in response to specific behavioural acts. 5. 5. Values for information present per act, information transmitted per act, and information per interaction per individual were calculated for each time interval using the data from the interindividual sequences. Information present (mean 2·73 bits per display) is similar to that of hermit crab acts, but information transmitted per act (mean 0·78 bits) and information transmitted per interaction (mean 1·82 bits) were higher. The higher value for information transmission may be the result of adaptation to cavity living and to potential injury (from strikes) during aggressive interactions. 6. 6. The rate of information transmission ranged from 0·013 to 5·46 bits per sec, a range similar to but somewhat broader than that of hermit crab transmission rates. The maximum rate is over twice that of the honey bee and three times that of the fire ant. Whether or not this reflects either the type of information transmitted or the means of transmission is not known.

Commercial catch of the Japanese mantis shrimp Oratosquilla oratoria (Stomatopoda, Squllidae) in Tokyo Bay was high during 1980s (good catch period), but dropped dramatically around 1992 and continued to be low during the 1990s (poor catch period). The major peak of larval abundance of O. oratoria appeared in June/July during the good catch period, while it appeared in August/September during the poor catch period. In the present study, we examined the temporal distribution of O. oratoria larvae during the transition from good catch period to poor catch period in Tokyo Bay. The larvae occurred from June to November, with a minor peak in July and a major one in September. The appearance of this major peak in September was considered to be an indication of the coming poor catch period. All of the eleven larval stages were collected during the research period. Stage-III larvae that were the first phase of pelagic life were numerically dominant. The propelagic-stage larvae (stages I and II) occurred only from June to September, while the larvae in the final stage of the planktonic phase (stage XI) occurred from July to November. Total duration of the larval phase was estimated to be one to two months.

Mantis shrimp Oratosquilla massevensis is an abundant marine crustacean in Egypt. It is common among the most important predators in many shallow, tropical and subtropical marine habitats. It is poorly understood as many species spend most of their life tucked away in burrows and holes. The objective of this study is to provide information on the histological characteristics of the ovary of female mantis shrimp O. massevensis and the morphology of the spawned egg, using scanning electron microscope. The ovaries showed a pronounced macroscopic differentiation in size and color with the maturation of the ovary, in six developmental stages namely: immature stage, previtellogenesis, primary vitellogenesis, secondary vitellogenesis, maturation and spent stage. Staining affinities of different structural components, size of different oocytes and nuclear sizes, as well as the follicular cells and their association with oocytes were used to differentiate between different oocyte developmental stages. Scanning electron micrographs of the spawned egg of O. massavensis revealed spherical forms of the egg with well noticed stalk or funiculus. The chorion is ornamented as a wrinkled layer with different textures. Two different yolky materials or matrices were observed, the first one constitutes a conical shaped hard matrix with glassy appearance, while the second one appears spongy with somewhat soft appearance.

SummaryStomatopod crustaceans, or mantis shrimp, are renowned for their complex visual systems. Their array of 16 types of photoreceptors provides complex color reception, as well as linear and circular polarization sensitivity [1–6]. The least-understood components of their retina are the UV receptors, of which there are up to six distinct, narrowly tuned spectral types [4]. Here we show that in the stomatopod species Neogonodactylus oerstedii, this set of receptors is based on only two visual pigments. Surprisingly, five of the six UV receptor types contain the same visual pigment. The various UV receptors are spectrally tuned by a novel set of four short- and long-pass UV-specific optical filters in the overlying crystalline cones. These filters are composed of various mycosporine-like amino acid (MAA) pigments. Commonly referred to as “nature’s sunscreens,” MAAs are usually employed for UV photoprotection [7, 8], but mantis shrimp uniquely incorporate them into powerful spectral tuning filters, extending and diversifying their preeminently elaborate photoreceptive arsenal.Video Abstract

SummaryUsing two UV-sensitive visual pigments and the UV-filtering properties of four mycosporine-like amino acids, mantis shrimp create six spectrally distinct UV receptors. This is yet another example of the unique ways in which mantis shrimp have adapted to extract information from their visual world.

The marine metazoan invertebrates exhibit a variety in eye design as great as their own phyletic diversity. Although this diversity can be conceptually reduced to a large number of variations on relatively few basic themes, as I shall demonstrate in this chapter, the variations, nonetheless, present an initially bewildering array. This can be traced, in part, to the multiplicity of photic environments inhabited by the huge assemblage of organisms conveniently lumped by one mammalian species as “invertebrates,” but it also reflects the large number of roughly parallel evolutionary lines, each based on a different ancestral eye type. Contributing to the complexity has been the independent evolution of radically different ocular organs in single lineages, such as the bivalve molluscs. The situation stands in sharp contrast to that of vertebrates, in which all extant eyes represent radiation from a single ancestral design.

The description of stages of the molt cycle in mantis shrimp (emphasizing Gonodactylus but compared in a number of Gonodactylidae, Squillidae, and Lysiosquillidae) includes data on texture, hardness, and color of the exoskeleton; behavior; and the micromorphology of the integument and developing setae. After stage A1, When the exoskeleton feels soft and soapy, and A2, when the abdomen attains parchment consistency, the exoskeleton continues to harden until stage C1, when the telson carinae can no longer be depressed with a fingernail. The propodus (C2) and the merus (C3) of the raptorial appendage are the last elements to become rigid. The meral spot achieves indistinct coloration at B1 and distinct but pale coloration at B2; body color continues to intensify until C4. Changes in behavior are particularly marked before and after the molt. After the molt defensive and avoidance behaviors characterize A1 and A2. Threatening increases from low to intense levels in A2 and B1. Striking and offensive behavior increase from weak to normal intensities from B2 to C4. One or two days before the molt, animals lower activity and dominance and feeding levels, exhibit reclusive behavior, and sometimes seal the cavity entrance. The morphology of setagenesis is particularly valuable for determining the stage of the molt after the exoskeleton hardens. The ratio of setae containing cellular contents throughout the lumen to those condensed into strands separates stages A2 through C3. “Cones,” although variable within and between individuals in some species, form initially in B2 and continue to condense through D. Initiation of C4, D0 and D1 overlaps variously in some individuals. Apolysis (D0) and morphogenesis of new setae (D1-D3) provide cues for identifying approach of the molt. Setagenesis and setal morphology differ among families, genera and some species of stomatopods. The structure and functional morphology of setae can be explained by the form of setagenesis. Passive swelling and active muscular peristalsis effect the shedding of the exoskeleton and setal eversion at the molt. The carapace and rostrum are shed as one unit. Patterns of meral sutures vary among taxa with enlargement of the merus and with subterminal or terminal ischiomeral articulation. Middorsal sutures open only on the sixth and seventh thoracic segments, suggesting loss of the first rather than the last abdominal segment and therefore a distant relationship to other eumalacostracans. Approximate durations of the molt stages in stomatopods are compared to those of 11 crustacean taxa. Extensive overlap seems to occur among midinterval stages, particularly in stomatopods. The developmental plateau occurs in different stages in different taxa. Late postmolt (C), associated with calcification, requires longer in more heavily calcified than in thinly calcified species, except for stomatopods. The physiological events immediately surrounding the the molt (A1–B1 and D3–D4) are compressed in time in crayfish, brachyurans, and especially in stomatopods. Behavioral adaptations maximize this compression of physiological events at the molt in stomatopods. These three groups also possess the most asymmetrical molt cycles of the crustacean taxa examined. It is hypothesized that these modifications of the molt cycle allow opportunistic molting and represent adaptations to agonistic behavior. Temporal variation in behavior and in color over the molt cycle may increase the potential for speciation by processes resembling neoteny.

A total of 36 samples of shrimp were examined from the region of the Buccaneer oil field, eighteen of which were representatives of the commercial species Penaeus aztecus and the rest were various other species: Penaeus duorarum (pink shrimp), Trachypenaeus duorarum (sugar shrimp), Squilla empusa (mantis shrimp), and Sicyonia dorsalis (chevron shrimp). The alkanes and deuteriated alkanes were completely separated by GC, so a mass spectrometer was not required for their detection and quantitation. To confirm the identities of individual compounds, however, some samples were examined by combined gas chromatography-mass spectrometry. Results show that only thirteen of the forty shrimp collected from the region of the Buccaneer oil field contained petroleum alkanes, and the majority of these were obtained from trawls immediately adjacent to the production platforms. It appears that shrimp caught in the region of the Buccaneer oil field are not appreciably tainted with hydrocarbons discharged from the production platforms. (JMT)

The electron microscopic structure of the myocardium of the mantis shrimp is descriped. Particular attention is paid to the organization of the nerve terminal and the sarcotubular system. The general appearance of this myocardium is characterized by deep invagination of the plasma membrane at the level of Z-band and large irregular shaped mitochondria. It possesses a very well developed sarcotubular system, consisting of the longitudinal system and two transverse elements making two sets of contact to each other. One forms dyad and the other forms triad at the level of M- and Z-band, respectively. The organization of the myoneural junction in this muscle is very simple and undifferentiated. In general, a special structural differentiation is invariably observed at both sides of the contact area. In spite of the fact that synaptic vesicles and a differentiated membrane are found at the naked process of this cardiac nerve, specialization such as subsynaptic fold formation has not been observed at the muscle side which is in contact with the nerve process. Observations made on the sarcotubular system and the nerve termination have been discussed with reference to their physiological significance.

One of the remarkable aspects of Antarctic benthic fauna is the almost complete absence of the crustacean order Decapoda. Many of the characteristic groups within this order are apparently completely absent, or at least not yet recorded. As one author has recently put it (Broch, 1961:27), ‘everybody who has worked in Antarctic Waters has been struck by the peculiar absence of crabs, lobsters, shrimps and prawns etc. in shallow waters’. Although this exemplifies the situation, it is not strictly correct as shrimps and prawns (Natantia) of at least two circumpolar species form a distinct feature of the shallow-water benthic fauna of such low-Antarctic areas (in the sense of Ekman, 1953) as South Georgia and such an extremely high-Antarctic area as McMurdo Sound. Thus it is the S.O. Reptantia, comprising the crayfish, lobsters, anomurans, hermit crabs and true crabs, that is apparently absent in this region though represented in Polar Arctic seas. The malacostracan order Stomatopoda, comprising the mantis shrimps, is similarly absent in the Antarctic, and in this case also absent in the Arctic.

Larvae of stomatopods (mantis shrimps) are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages), alima and erichthus (the latter two representing later larval stages). These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoological Museum, University of Copenhagen and were collected during the Danish Dana Expedition round the world 1928-30. These new larval types all represent erichthus-type larvae, especially differing in their shield morphologies. The shield morphology ranges from almost spherical to rather disc-like, with sometimes extremely elongated spines, but only a general systematic assignment of the larvae was possible. Further investigations of these larvae are crucial to understand their life habits and ecological impact, especially as stomatopod and other crustacean larvae might have a much more important position in the marine ecosystems than their corresponding adults.