Spatio-Temporal Dynamics of Field Cricket Calling Behaviour: Implications for Female Mate Search and Mate Choice

Amount of calling activity (calling effort) is a strong determinant of male mating success in species such as orthopterans and anurans that use acoustic communication in the context of mating behaviour. While many studies in crickets have investigated the determinants of calling effort, patterns of variability in male calling effort in natural choruses remain largely unexplored. Within-individual variability in calling activity across multiple nights of calling can influence female mate search and mate choice strategies. Moreover, calling site fidelity across multiple nights of calling can also affect the female mate sampling strategy. We therefore investigated the spatio-temporal dynamics of acoustic signaling behaviour in a wild population of the field cricket species Plebeiogryllus guttiventris. We first studied the consistency of calling activity by quantifying variation in male calling effort across multiple nights of calling using repeatability analysis. Callers were inconsistent in their calling effort across nights and did not optimize nightly calling effort to increase their total number of nights spent calling. We also estimated calling site fidelity of males across multiple nights by quantifying movement of callers. Callers frequently changed their calling sites across calling nights with substantial displacement but without any significant directionality. Finally, we investigated trade-offs between within-night calling effort and energetically expensive calling song features such as call intensity and chirp rate. Calling effort was not correlated with any of the calling song features, suggesting that energetically expensive song features do not constrain male calling effort. The two key features of signaling behaviour, calling effort and call intensity, which determine the duration and spatial coverage of the sexual signal, are therefore uncorrelated and function independently.     

Burden of Liver Disease among Community-Based People Who Inject Drugs (PWID) in Chennai,India

Background and Objective

We characterize the burden of liver disease in a cohort of PWID in Chennai, India, with a high prevalence of HCV.

Materials and Methods

1,042 PWID were sampled through community outreach in Chennai. Participants underwent fasting blood draw, questionnaire and an examination that included liver stiffness assessment using transient elastography (Fibroscan) and assessment of steatosis via ultrasound.

Results

The median age was 39 years, all were male, 14.8% were HIV infected and 35.6% were HCV antibody positive, of whom 78.9% were chronically infected (HCV RNA positive). Median liver stiffness was 6.2 kPA; 72.9% had no evidence of or mild stiffness, 14.5% had moderate stiffness, and 12.6% had evidence of severe stiffness/cirrhosis. Prevalence of severe stiffness/cirrhosis was significantly higher among persons who were older, had a longer duration of injecting drugs, higher body mass index, higher prevalence of insulin resistance, higher prevalence of steatosis, higher HCV RNA levels and evidence of alcohol dependence. An estimated 42.1% of severe stiffness/cirrhosis in this sample was attributable to HCV. 529 (53.0%) had some evidence of steatosis. Prevalence of steatosis was higher among those who had larger waist circumference, insulin resistance, higher HDL cholesterol and a history of antiretroviral therapy.

Conclusions

We observed a high burden of liver disease in this relatively young cohort that was primarily driven by chronic HCV infection, metabolic factors (insulin resistance and steatosis) and heavy alcohol use. Interventions to improve access to HCV treatment and reduce alcohol use are needed to prevent further progression of liver disease.     

The influence of salinity on a tropical estuarine shipworm Nausitora hedleyi Schepman (Bivalvia - Teredinidae)

Species belonging to the genus Nausitora (Bivalvia - Teredinidae) are generally confined to brackish waters. In the Cochin backwaters, a tidal estuary on the southwest coast of India, this genus is represented by the species N. hedleyi Schepman. Fresh settlement of the species in the area is noticed only during the period of low salinity, though the species of found to exist, throughout the year. Tests conducted to ascertain the effect of salinity changes on the activity of the borer showed that though it can endure a wide range, the optimum salinity range for early development was from 11.24–14.54%.     

Observations on the sex characters of the timber-boring sphaeromids (Isopoda) of the Indian waters

The timber-boring isopods (family Sphaeromidae) namely Sphaeroma terebrans, S. annandalei, S.a. travancorensis and S. triste occurring in Indian waters were studied for primary and secondary sex characters. A concise comparative account of the primary and secondary sex characters such as penial sacs, appendix masculina and oostegites has been given. The sexual dimorphism exhibited by the seventh pair of peraeopods of S. terebrans is explained fully. The sexual disparity in the body length of two species of Sphaeroma has also been described.     

Blood coagulation and immunological changes associated with frostbite at high altitude

In 15 cases of frostbite among soldiers stationed between 3690 and 5540 m altitude in the Himalayas investigations of blood coagulation and immunoglobulins were carried out within 24 hours, after 4 weeks and one year. In frostbite evidences of intravascular coagulation were the presence of increased amounts of FDPs in serum, reduction of plasma fibrinogen, fall in platelet counts and haematocrit, increased platelet adhesiveness, and prolonged euglobulin lysis time. Marked lowering of antithrombin III and protease inhibitors -1 antitrypsin and 2 macroglobulin indicate their increased consumption in the pathological process. Increased immunolglobulins with relative decrease of albumin and the appearance of cryoglobulins in the form of IgG, IgA and IgM complexes, also seem to promote platelet aggregation and release reaction. Anticoagulant therapy combined with antiplatelet adhesive drugs, if instituted in the early stages of frostbite might be successful in preventing damage resulting from intravascular coagulation.     

Immune response in human subjects at high altitude

Levels of immunoglobulins were determined in persons exposed to high altitude. The individuals studied included high altitude natives, sea level residents at high altitude for 2 years, and recent arrivals at high altitude. Increased IgG and IgA levels were found in high altitude natives and sea level residents at high altitude for 2 years when compared with sea level residents. In recent arrivals marked increase of IgG and IgG levels and slight rise in IgM was seen. Recent arrivals who suffered from high altitude pulmonary oedema showed marked elevation of IgG, IgM, and IgA. Immunoglobulin responses to both primary and secondary TAB inoculation were of a higher magnitude and more sustained at high altitude than at sea level.     

Harpacticoid copepods associated with the seagrass Halophila ovalis in the Ashtamudi Estuary,south-west coast of India

A temporal study of harpacticoid copepod populations associated with the seagrass Halophila ovalis was undertaken in the Ashtamudi Estuary, south-west coast of India. A total of 19 species representing 8 families was recorded in this assemblage. Harpacticoids formed 7.52% of the total phytal meiofauna. At the species level, harpacticoids exhibit parallel assemblages with phytal zones, found in other localities.     

Development of an antibody against a 170-kDa fragment of fibroin isolated from cocoon fibres of Bombyx mori.

A simple method for the isolation of denatured fragments of the fibroin protein from cocoon fibres by alkali solubilization is discussed. This 170-kDa antigen has been purified and used to raise the polyclonal antibody in rabbit. The specificity of this antibody to the purified cocoon protein has suggested strong immunoreactivity up to a titre of 1:5000 dilution of the antibody. Further, dot-blot analysis with the tissue extracts from silk glands of different larval stages (3rd to 5th) reveals that this antibody reacts showing a stage-specific increase in the intensity of the colour, correlating well with the in-vivo expression of the silk protein. This study suggests the availability of a specific polyclonal antibody that detects the native fibroin with no crossreactivity with other tissue proteins.