Crossota

Abstract: Di stribution and abundance of hydromedusae from the exclusive economic zone of the west and east coasts of India is carried out based on zooplankton collections (on board FORV Sagar Sampada) during the period 1985-1990. The 661 sampl es collected from 21l cruises of west and east \.:oasts were analysed. Eighty species of 43 genera were observed. In the west coast highest population density was found from th e southwest region whereas in the eas t coast it was from the north eastern part . Aglaura hemistoma was the most dominant species of west coast while Liriope tetraphylla was that of the east coast. Solmundella bitentaculata was the next abundant species of both the coasts. Cyta eis tetrastyla. Rhopalonema velatum and Crossota alba were the next commonly occurring species of west coast while Rhopalonema velatum. Cyta eis tetrastyla, Bougainvillia fulva and Phialidium hemisphaericum were the common forms of the east coast. Aequorea conica was noticed in swarms from west coast. The study indicates the richness of hydromedusae along the coastal waters of India. Gelatinous zooplankton often function as key organisms in pelagic ecosystem l . Hydromedusae are important in the sense that they are exclusively carnivores and moreover, they are predators and hence they compete with other predators like fish larvae. During the International Indian Ocean Expedition, (I.I.O.E.) coastal areas were not thoroughly sampled. The Exclusive Economic Zone (EEZ) of India fOnTI about two-thirds of India's land mass . The available information on the distribution and abundance of hydromedusae are mainly for the west coast2-5. Ganapati & Nagabhushanam6 reported the seasonal distribution of hydromedusae from Visakhapatnam coast. Distribution of hydromedusae based on the I.I.O .E. samples were studied by a few authors7-9. The present study is focu sed to fill the lacuna and it is based on the materials collected on board FORV Sagar Sampada during the period 19851990 fr om the EEZ of both west and east coasts of India.

Abstract: The density of overwintering Plautia crossota stali Scott in fallen leaves changed similarly in seven districts of Wakayama Prefecture, showing a remarkable peak in 1996. There was a highly positive correlation between the number of airborne pollen of sugi (Cryptomerica japonica D. Don) and the density of P. crossota stali overwintering in fallen leaves. There also was a highly positive correlation between the number of airborne sugi pollen and the number of light trap catches of P. crossota stali and Glaucias subpunctatus (Walker) in April–July of the following year. Since the overwintering density of the two stink bugs seemed to depend on the number of airborne sugi pollen, which is closely related to cone production, the number of airborne pollen is considered to be a useful index for forecasting the population densities of these two stink bugs in the following spring-summer season.

Abstract: Several species of small, red, deep-sea Trachymedusae have been described and then re-described over the past 20 years, leading to some confusion in the scientific literature. This paper provides an overview of three genera (Benthocodon, Crossota, and Pectis) in the family Rhopalanematidae (Cnidaria: Hydrozoa) that have been observed and examined both in the field and in the laboratory. Twenty years of in situ observations in Monterey Bay indicate that two of the genera, Benthocodon and Pectis, are often associated with the benthic boundary layer and can occur in dense patches. They have been observed resting on soft sediments with their subumbrellar surface down but are also to be found swimming up to several hundred meters above the bottom. Individuals in the genus Crossota tend to be solitary and more pelagic in nature. Although Crossota may be found near the bottom as well, down to depths of 4000 meters, they have not been observed resting on the bottom. The three genera are morphologically similar and difficult to distinguish. As a group, they are small (< 5 cm) and sometimes darkly pigmented, making in situ identifications challenging. We show that these three genera can be differentiated morphologically and we provide a key to the genera and species common in Monterey Bay. Further, the genera differ in their depth distribution and behavior. Molecular genetics suggest that the genera and species are distinct from each other but that their taxonomy is in need of thorough revision. This paper reviews the generic characteristics along with species identifications and provides images and video (supplemental material) that may be helpful in identification.

Abstract: Trissolcus plautiae is a solitary and dominant parasitoid of the brown-winged green bug, Plautia crossota stali. The development of immature stages of T. plautiae in the eggs of P. crossota stali at 25°C, 16L–8D and 50±10% RH was investigated. T. plautiae was comfirmed to have three larval instars, and the mandibles were the characteristic of the 1st-instar larvae. The developmental period in males and females was estimated at 16.4 (in hours) and 16.3 in eggs, 40.0 and 39.4 in the 1st instars, 15.8 and 18.5 in the 2nd instars, 48.1 and 57.3 in the 3rd instars, 16.9 and 20.8 in prepupae, and 118.6 and 152.1 in pupae, respectively. The volume of parasitoid eggs reached their maximum 18 h after oviposition, just before hatching. The body length of larvae increased till the end of the 2nd instar, and decreased slightly in the 3rd instar. The egg volume and the body length were not significantly different between males and females of T. plautiae. Adult males first emerged 264 h after oviposition, and females emerged 48 h later than males.