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1. Diel rhythms of foraging activity by animal flower visitors can reflect niche partitioning and are considered an important component of selection on floral traits. However, it has been notoriously difficult to obtain objective information on the patterns of flower visitation by crepuscular and nocturnal insects. 2. Motion-activated cameras were used for field-based studies of hawkmoth foraging behaviour on six African plant species. 3. The results showed that short-tongued hawkmoth species forage mainly around dusk and then sporadically throughout the night, whereas long-tongued hawkmoth species feed consistently throughout the night, with a peak shortly before midnight. 4. These results provide the first quantitative estimates of diel patterns of interactions between multiple hawkmoth and plant species and, when combined with qualitative reports from other studies, suggest that differences in diel activity between the two main hawkmoth functional groups (short- and long-tongued) are consistent across the Old and New Worlds.  相似文献   
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Doxorubicin (DOX) is an anthracycline drug used for cancer treatment. However, its treatment is contiguous with toxic effects. We examined the nephroprotective potential of A. hydaspica polyphenol-rich ethyl acetate extract (AHE) against DOX persuaded nephrotoxicity. 36 male Sprague Dawley rats were randomly assorted into 6 groups. Control group received saline; DOX group: 3 mg/kg b.w. dosage of DOX intraperitoneally for 6 weeks (single dose/week). In co-treatment groups, 200 and 400 mg/kg b.w AHE was given orally for 6 weeks in concomitant with DOX (3 mg/kg b.w, i.p. injection per week) respectively. Standard group received silymarin 400 mg/kg b.w daily + DOX (single dose/week). Biochemical kidney function tests, oxidative stress markers, genotoxicity, antioxidant enzyme status, and histopathological changes were examined. DOX caused significant body weight loss and decrease kidney weight. DOX-induced marked deterioration in renal function indicators in both urine and serum, i.e., PH, specific gravity, total protein, albumin, urea, creatinine, uric acid, globulin, blood urea nitrogen, etc. Also, DOX treatment increases renal tissue oxidative stress markers, while lower antioxidant enzymes in tissue along with degenerative alterations in the renal tissue compared to control rats. AHE co-treatment ameliorates DOX-prompted changes in serum and urine chemistry. Likewise, AHE treatment decreases sensitive markers of oxidative stress and prevented DNA damages by enhancing antioxidant enzyme levels. DOX induction in rats also caused DNA fragmentation which was restored by AHE co-treatment. Moreover, the histological observations evidenced that AHE effectively rescued the kidney tissue from DOX interceded oxidative damage. Our results suggest that co-treatment of AHE markedly improve DOX-induced deleterious effects in a dose-dependent manner. The potency of AHE co-treatment at 400 mg/kg dose is similar to silymarin. These outcomes revealed that A. hydaspica AHE extract might serve as a potential adjuvant that avoids DOX-induced nephrotoxicity.  相似文献   
4.
Flowering in Arabidopsis is accelerated by a reduced ratio of red light to far-red light (R/FR), which indicates the proximity of competitive vegetation. By exploiting the natural genetic variation in flowering time responses to low R/FR, we obtained further insight into the complex pathways that fine-tune the transition to flowering in Arabidopsis. The Bla-6 ecotype does not flower significantly earlier in response to low R/FR, but is still able to display other features of shade avoidance, suggesting branching of low R/FR signalling. Here we show that the muted flowering response of Bla-6 is due to high levels of the floral repressor FLOWERING LOCUS C (FLC), conferred by a combination of functional FLC and FRIGIDA ( FRI ) alleles with a 'weak' FY allele. The Bla-6 FY allele encodes a protein with a corrupted WW binding domain, and we provide evidence that this locus plays a key role in the natural variation in light quality-induced flowering in Arabidopsis. In Bla-6, FLC blocks promotion to flowering by reduced R/FR by inhibiting expression of the floral integrator FLOWERING LOCUS T ( FT ) in a dose-dependent manner. Reduction of FLC removes this obstruction, and Bla6 plants then exhibit strong induction of FT and flower early in response to a low R/FR signal. This paper illustrates the intricate interaction of environmental signals and genetic factors to regulate flowering in Arabidopsis.  相似文献   
5.
Impacts of sheep ticks Ixodes ricinus on livestock, gamebirds and wildlife are of concern across Europe. The present study describes livestock and tick management by 36 farmers from three upland sites of conservation importance in North Wales, where farmers consider that ticks have increased during the last 25 years. Sheep, average densities of 2.0 animals per ha were treated with pour‐on acaricides in spring, again in July, and also when removed from the moor in autumn. Given acaricide efficacy rates, sheep were susceptible to tick bites for half the period on the moor. Sheep from 17 farms were examined for ticks. Infestations were similar between farms and in relation to the acaricide used, averaging 9.3 ticks per sheep, although they were lower where the interval between successive acaricide treatments was shorter. Repeated sampling of sheep and red grouse chicks showed no annual difference in tick burdens on grouse chicks, which averaged 6.2 ticks per chick, although there were three‐fold fewer ticks on sheep in 2018 than in previous years. Tick bite rates on sheep and grouse were higher than elsewhere in the U.K. Most farmers interviewed would aim to improve their tick management using longer‐lasting acaricides and treating sheep more frequently, although they would need advice and financial help, which is currently unavailable via Government funded agri‐environment schemes.  相似文献   
6.
The use of miniaturized video cameras to study the at‐sea behavior of flying seabirds has increased in recent years. These cameras allow researchers to record several behaviors that were not previously possible to observe. However, video recorders produce large amounts of data and videos can often be time‐consuming to analyze. We present a new technique using open‐source software to extract bank angles from bird‐borne video footage. Bank angle is a key facet of dynamic soaring, which allows albatrosses and petrels to efficiently search vast areas of ocean for food. Miniaturized video cameras were deployed on 28 Wandering Albatrosses (Diomedea exulans) on Marion Island (one of the two Prince Edward Islands) from 2016 to 2018. The OpenCV library for the Python programming language was used to extract the angle of the horizon relative to the bird’s body (= bank angle) from footage when the birds were flying using a series of steps focused on edge detection. The extracted angles were not significantly different from angles measured manually by three independent observers, thus being a valid method to measure bank angles. Image quality, high wind speeds, and sunlight all influenced the accuracy of angle estimates, but post‐processing eliminated most of these errors. Birds flew most often with cross‐winds (58%) and tailwinds (39%), resulting in skewed distributions of bank angles when birds turned into the wind more often. Higher wind speeds resulted in extreme bank angles (maximum observed was 94°). We present a novel method for measuring postural data from seabirds that can be used to describe the fine‐scale movements of the dynamic‐soaring cycle. Birds appeared to alter their bank angle in response to varying wind conditions to counter wind drift associated with the prevailing westerly winds in the Southern Ocean. These data, in combination with fine‐scale positional data, may lead to new insights into dynamic‐soaring flight.  相似文献   
7.
Geographic variation in sexual dimorphism of tooth size was assessed for the red fox Vulpes vulpes (Linnaeus, 1758) across the whole northern range of the species. Twenty-one measurements of tooth size and skull length were taken from 2849 specimens (1577 males and 1272 females) originating from 12 Nearctic and 25 Palearctic localities. The index of sexual dimorphism was calculated as a quotient of the mean measure of certain characters in males by the respective mean in females ( M m/ M f). In the whole range, the males were larger than females and mean dimorphism index of tooth size ranged from 1.01 to 1.06. On average, the tooth measurements in males were 3.6% larger than in females. The highest dimorphism was observed in the canines. Dimorphism of tooth size was higher in the Palearctic than Nearctic. Statistically significant differences between regions were found for lengths of C1, C1 and M1. In the Palearctic, higher values of the dimorphism indices were observed particularly in the southern parts of the Eurasian range of the red fox and in Great Britain. For a few metrical traits, sexual dimorphism indices presented significant relations to some geo-climatic variables. The geographic pattern of size dimorphism in the red fox seems to be shaped by sexual selection, intraspecific and interspecific competition and population density.  相似文献   
8.
Thefirst-instar nymph and the adult female of Kermes echinatus Balachowsky (Hemiptera, Coccoidea, Kermesidae) are described and illustrated. This species is compared with Kermes vermilio Planchon, a morphologically similar species known in the Palaeractic region.  相似文献   
9.
Using ruthenium red as a macromolecule, endocytosis was demonstrated in the plerocercoid of Ligula intestinalis and adult Schistocephalus solidus. Uptake, transport across the tegument, and exocytosis across the basal plasma membrane occurred within 6 min. The types of vesicles in the tegument of L. intestinalis are redescribed and their former classification is modified. The vertical and longitudinal distribution of pinosomes in the tegument of adult S. solidus and L. intestinalis plerocercoids were determined. The possible role of macromolecular uptake in the economy of pseudophyllidean tapeworms is discussed with particular reference to growth and defence of an unencysted larval stage in the tissues of the intermediate host.  相似文献   
10.
Biosorption potential of Azolla microphylla for acid red 88 from aqueous solution was investigated under laboratory conditions as a function of initial pH and temperature. The algal biomass exhibited the highest dye sorption capacity at optimum conditions of pH 3 and temperature 30°C. The experimental isotherms were analyzed using five two-parameter models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Flory-Huggins) and five three-parameter models (Redlich-Peterson, Sips, Khan, Radke-Prausnitz, and Toth). Three error analysis methods were used to evaluate the experimental data: correlation coefficient, residual root mean square error (RMSE), and chi-square test to find the best fitting isotherm. In particular, Langmuir (two-parameter) and Khan (three-parameter) models described the dye biosorption isotherm data well at all pH and temperature conditions examined.  相似文献   
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