Regular exposure to a given stressor poses selective pressure towards increased resistance. In high temperature environments this can be mediated through physiological and biochemical adjustments that lead to increased resistance to heat coma. Such adjustments may influence complex traits such as locomotor activity through cascading effects. Alternatively, changes in locomotor activity may change the exposure to the stressor and, thereby, the importance of the physiological and biochemical adjustments. In this experiment we analysed how selection for heat shock resistance may affect locomotor activity at high temperatures in Drosophila melanogaster. We compared 2 lines selected for heat shock (HS) and cold shock (CS) resistance at 4 constant high temperatures (28 to 38°C). We also tested the importance of heat shock protein (Hsp) expression by comparing locomotor activity at the same temperatures of a heat-sensitive mutant line (Hsf 0 ), where the heat shock factor (Hsf) is non-functional at high temperatures, with that of a rescued mutant line (Hsf + ) with a functional Hsf re-inserted. At moderately stressful temperatures (28 and 34°C), flies from the Hsf 0 line were more active than flies from the Hsf + line, whereas this was reversed at higher temperatures. In the selection lines, the CS flies were more active at 28°C but this was reversed at 34 and 36°C, whereas no difference was observed at the most stressful temperature (38°C). This suggests that the lines selected for increased cold tolerance were more stressed at moderately high temperatures and, therefore, more active in the attempt to escape the stress, whereas at higher temperatures, their locomotor activity was more compromised than in flies from the lines selected for increased heat resistance.
Cladocera is investigated in waterbodies of Vinh Long province during 2013 to 2014. Samples were collected from eight stations. 18 cladocera species belonging to 14 genus, 7 family, 2 order and 1 class were observed. In that, 14 species were recorded in 2013, and 15 species were recorded in 2014. The species composition of order Anomopoda always dominates in waterbodies. The species Grimaldina brazzai Richard, 1892 (Macrotricidae, Anomopoda, Branchiopoda) are redescribed from material collected in Co Chien river of Vinh Long province in 2013. The results have identified 04 female individuals, but no male individuals of G. brazzai are recorded. Morphological characteristics of G. brazzai are as descriptive as Richard (1892), Brook (1956) and Idris (1983). Morphological characteristics of Grimaldina và G. brazzai female are described and illustrated details by Optikam and Adobe Illustrator CS5. Some morphology characters used to identify, e.g., eye, head pores, Labral plate, Antennule I - II, postabdomen. The genus Grimaldina comprises only one species G. brazzai. This species has been recorded in lakes and rice fields of Brazil, Thailan, Lao, Philippines, Indonesia, Malaysia, Cambodia and Singapore, rare species. The first time in Vietnam Shirota (1966) was recorded this species in South Vietnam, but he has not describe.
In a total of four surveys at eight sites in some major rivers in Vinh Long province during 2013 to 2014, 18 species of cladoceran, belonging to 14 genera, 7 families and 2 orders, were recorded. The cladocerans fauna in Vinh Long province is recognized as moderate diverse, and the species recorded were mostly common species. Among 18 species, Grimaldina brazzai Richard, 1892 is a rare species. A total of four females specimens of species G. brazzai were collected at the Co Chien river, but male specimens were absent. The specimens were morphologically identified as G. brazzai described first by Richard (1892), followed by Brook (1959), Idris (1983), Smirnov (1992) and Hollwedel (2003). Grimaldina brazzai is currently the only one species in the genus Grimaldina and has been recorded in several tropical countries, such as Brazil, Thailand, Laos, Philippines, Indonesia, Malaysia, Cambodia and Singapore. They occur in lakes and rice fields, but population of this species is very limited in nature. In Vietnam, this species was first recorded in South Vietnam by Shirota (1966), but has not been described since then until recently Sinev & Korovchinsky (2013) recorded this species in the Cat Tien National Park, Dong Nai province, South Vietnam.
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