Seasonal changes in the trade-off among fig-supported wasps and viable seeds in figs and their evolutionary implications

What the real trade-off is among fig-supported wasps and the viable seeds of figs is heatedly debated in the studies of fig/fig wasp mutualism. In the present study, we collected wasp offspring (galls) and the viable seeds of premature fruits, and determined the foundress number in receptive fruits and all the types of wasps supported by Ficus racemosa L. during both the rainy and dry seasons in Xishuangbanna, China. The data show that the galls were positively correlated with viable seeds (n=32;r=0.74; P < 0.001) when the proportion of vacant female flowers (PVFF) was high, in April (68.0%), and were negatively correlated with viable seeds (n=48;r=-0.59; P < 0.05) when PVFF were limited (PVFF 42.6%) during a colder month (January). The mean foundress number per fruit during the colder months is significantly lower than during the warmer months (F-5,F-603 = 27.9; P < 0.001) and pollinator wasps can live longer during the colder months, During the colder months, the proportions of non-pollinators and wasp offspring are higher than those found during other months, whereas the proportion of viable seeds is not different compared with that of other months. Non-pollinator wasps tend to oviposit the female flowers that have been oviposited by pollinator wasps. The non-pollinators only negatively affect pollinator wasps and there is no obvious negative effect of non-pollinator wasps on viable seeds, so ovipositing by non-pollinator wasps will not result in the extinction of the figs during the process of evolution. The results of the present study indicate that figs can allow less foundresses to be in fruit cavities when PVFF are limited, which provides supporting evidence for the previous assumption that the plants have developed a mechanism to maintain a stable system because of the conflicts between the parties involved.

Seasonal changes in the biochemical composition of liver in Garra mullya (Sykes)

Seasonal changes taking place in the biochemical constituents of liver of G. mullya are reported. An inverse relationship was noticed in the variation of fat and water. Maximum fat contents were observed during june-july. Reserve fat was utilized through gluconeogenesis during the spawning months. Protein and glycogen percentages were comparatively higher in liver than in the muscles and gonads. Decline in the glycogen content was associated with spawning during July to November. Nutritive values have shown more energy contents in the liver during pre-spawning months.

Transportation of fish - 3. Biochemical changes in fish during transportation in insulated containers

The changes in the biochemistry of different varieties of iced fish during transportation in thermocole lined second hand tea chests from Veraval to Bombay and Delhi are discussed. The moisture increased for all the varieties except for eel and hilsa at Bombay. TMAN and TVN increased in all cases. Maximum increase of TMAN and TVN was observed in seer fish.

Studies on radiation pasteurisation of medium fatty fish 1. Control of radiation induced oxidative changes in white pomfret (Stromateus cinereus) by vacuum packaging

Marked differences were observed in proximate biochemical compositions of the skin and muscle of white pomfret. The skin showed comparatively higher content of extractable lipids and was more susceptible to radiation-induced oxidative changes like development of rancid odours and yellow discolouration than the muscle. Irradiation of skin samples under vacuum suppressed these changes. The present paper also reports on the efficacy of vacuum packaging in controlling oxidative rancidity and yellow discolouration in white pomfret skin subjected to irradiation and subsequent storage at 0-2°C.

Technological aspects of preservation and processing of edible shell fishes V. Cold storage changes in mussels (Mytilus edulis) and clams (Villortia [i.e. Villorita] sp.)

The changes in chemical, bacteriological and organoleptic qualities of mussels and clams during freezing and subsequent frozen storage have been studied in relation to the holding time in ice prior to freezing and the shelf-life of the product is determined.

Freeze drying of fishery products: Part IV - Biochemical changes occurring in prawn muscle during freezing, freeze drying and prolonged storage of the freeze dried product

The changes occurring in water and salt extractable protein and non-protein fractions in prawn muscle of different species during freezing, freeze drying and subsequent prolonged storage have been studied. There is no denaturation of water extractable proteins, whereas salt extractable proteins were rendered insoluble to the extent of 21% due to freeze drying. The freeze dried products remained in good edible condition for 32 months of storage up to which storage characteristics were followed.

Biochemical differences between the red and white meat of tuna and changes in quality during freezing and storage

The differences between the white and red (dark) meat of tuna (Katsuwonus pelamis) in chemical, physical and organoleptic aspects and the rate and pattern of spoilage during freezing and subsequent storage are discussed in this communication. In the indices studied distinct difference is seen between the white and red meat as well as in the head, middle and tail portions of the same fish. The characteristic colour of tuna meat is due to the presence of haemoglobin and myoglobin, the concentrations of which are about 5 times more in red meat than in white meat. The shelf-life of the frozen material varies with the type of the pack, that is, whole fish>chunks>fillets; the fillets being adversely affected during frozen storage.

Some changes in the physical qualities of muscle lipid of the freshwater murrel, Ophicephalus striatus (bloch.) during storage

The present communication reports the changes in the specific gravity, coefficient of viscosity, fluidity and surface tension of the muscle lipid of O. striatus, a common freshwater murrel, when stored at room temp (32 ± 2°C) The specific gravity of muscle lipid was found to rise from 0.894 to 0.912 during the first 25 days of storage but registered the highest (0.925) when stored for 50 days. Surface tension seemed to rise with the duration of storage. This was, presumably, due to an increase in the forces with which the molecules in the surface of the lipid tended to compress the molecules below to the smallest possible volume. During the period of storage marked changes seemed to occur in the direction of an increase in the value of the coefficient of viscosity and a reciprocal decline in the fluidity. Evidently, the observed increase in the viscosity seemed to be the result of increased internal friction between different molecular layers of the lipid, whereas a decline in the fluidity was perhaps the consequence of its inverse correlation with the coefficient of viscosity.

Further studies on changes in protein fractions of fish muscle during storage in ice

The changes in the major protein nitrogen fractions of two commercially important fishes of Indian waters, viz., mackerel (Rastrelliger kanagurta) and lactarius (Lactarius lactarius), during storage in ice are reported. The significance of the findings is discussed in comparison with the results of a similar study on two species of marine prawns and oil sardine, reported earlier.

Chemical changes in skin mucin as an index of early stages of spoilage in fish

Results of a preliminary investigation on the overall chemical nature of fish skin mucin in lung fish, Clarias batrachus, with special reference to water soluble low molecular weight compounds, are presented. Changes observed during room temperature spoilage have been studied with a view to present a new approach towards the assessment of freshness in fish inspection. pH of the mucin was distinctly alkaline (8.2) and remained unchanged during spoilage. Much of the nitrogen was found to be present in the glycoprotein fraction. Free amino acids and purine bases were present in appreciable quantities in the aqueous extracts which registered a significant increase after 10 hrs. Post-mortem increase in total solids was accompanied by a slight rise in protein nitrogen which may indicate tissue breakdown. Increase in TVN was also observed to occur earlier in the outside mucin as compared to the inside muscle. Presence of free sugars or sialic acid could not be confirmed nor was there any indication of cholesterol and lipoid material as stated in earlier literature.

Seasonal changes in the biochemical composition of ovary in Heteropneustes fossilis (Bloch)

Seasonal changes in the biochemical composition of ovary in H. fossilis are reported. An inverse relationship was noted in fat and water contents. Maximum fat was observed in June and lowest in December. Protein and ash were generally low during winter and high during summer or monsoon months. Variations in the cholesterol content were more or less identical to those of the fat.

Biochemical changes of fish fingers held at frozen storage

The frozen storage characteristics of fish fingers made out of two different species, differing in lipid content for a period of six months are outlined. The study reveals that the lipid content of the fish meat used for making fish fingers influences the storage pattern in terms of the chemical parameters like peroxide value, thiobarbituric acid value and free fatty acids. The introduction of monosodium glutamate has improved the flavour of the fish fingers. Further, the application of batter on the fish fingers imparted some protective effect in the case of semi-fatty fish.

Changes in the muscle of three Indian major carps during frozen storage

Chunks of Labeo rohita, Cirrhinus mrigala and Catla catla wrapped in polythene film were stored at -8 to -10°C in the freezer cabinet of the refrigerator. It was found that L. rohita and C. mrigala were acceptable up to 33 days and C. catch up to 35 days. Total volatile base nitrogen, free fatty acids and degree of sponginess of the samples showed increasing trend during frozen storage.