Mitochondrial genetic structure reflects the geographical variation of elytral polymorphism frequency in Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

Many ladybird species are known to have an elytral colour polymorphism, which indicates geographical variation. The ladybird beetle Cheilomenes sexmaculata (Fabricius) exhibits elytral colour polymorphism and has expanded its distribution from 33°N to 36°N in Japan over 100 years since 1900. The mitochondrial COI gene haplotypes were integrated into two haplotype groups, with one group existing at higher frequencies in lower latitudes, the other group appearing at higher frequencies in higher latitudes. In addition, the dark morph types of this species increase with latitude, whereas the light types appear at higher relative frequencies in lower latitudes.In the present study, we first determined the morph types of individuals and examined the mitochondrial DNA COI gene. Second, we investigated the relationship between the genetic population structure based on the mitochondrial DNA COI gene and the morph types’ geographical variation. Results indicated that the mtCOI genetic structure was associated with the morph types by latitude; specifically, the haplotype group existing at higher frequencies in lower latitudes tended to be light morph types. In contrast, the haplotype dominant in higher latitudes more frequently exhibited dark morph types, indicating that dark morph types in the higher latitude genetic group may have led the distributional expansion toward higher latitudes since 1900 rather than the lower latitude light morph types.     

Symbiotic growth of indigenons white clover (Trifolium repens) with local Rhizobium leguminosarum biovar trifolii

To study a possible adaptation of the symbiosis between white clover (Trifolium repens L.) and Rhizobium leguminosarum biovar trifolii with regard to light and temperature at northern latitudes, local seed populations of white clover and isolates of R. leguminosarum biovar trifolii from 3 different latitudes in Norway, 58°48'N, 67°20'N and 69°22'N, were used. The commercial cultivar Undrom was used as a reference plant. The experiments were done at 18 and 9°C under controlled conditions in a phytotron during the natural growing season at 69° 39'N. Growth of the plants was evaluated by number and size of leaves, dry matter production and total N-content. At 18°C the white clover plants were harvested twice while at 9°C there was only one growth period. The results from first harvest at 18°C and total growth at 9°C, showed that white clover populations from northern Norway had a lower growth potential than the population from the south and cv. Undrom. This difference was not apparent in the second growth period at 18°C. Growth of the plants from seeds to first harvest was enhanced by mineral nitrogen compared to plants dependent on Rhizobium only. However, after a second growth period dry weight and total nitrogen content of the plants with nitrogen fixation were comparable to the plants receiving mineral nitrogen. Statistical analysis showed that the most important factor for the variation in dry matter production was the plant population. Within the populations at 9°C and at first harvest at 18°C, there were no significant differences in dry matter production with different Rhizobium inoculum. In the second growth period at 18°C, different inoculum gave significantly different amount of dry matter within a population. The results showed a significant interaction between plant population and Rhizobium inoculum, and the results indicated that plants from the north gave higher yield when nodulated by Rhizobium from the north than from the south.     

Niche separation between <Emphasis Type="Italic">Encarsia dispersa</Emphasis> and <Emphasis Type="Italic">Encarsia guadeloupae</Emphasis>, two biological control agents of the spiraling whitefly <Emphasis Type="Italic">Aleurodicus dispersus</Emphasis>, in Benin,West Africa

The spiraling whitefly Aleurodicus dispersus (Russell) is an insect pest that causes substantial damage to ornamental plants, shade trees and food crops. It was first observed in Benin in 1993. Two host specific parasitoids, Encarsia dispersa and E. guadeloupae, fortuitously introduced with its host, were recovered in the second half of 1993 in Southern Benin. Survey results from 1993 to 1995 (already published) showed the decline in the population of A. dispersus due to the parasitoids, and the spread from Cotonou (6°10′N) in a northern directions of both parasitoids and their host. Results from similar field surveys from 1996 to 2003 document that the spiraling whitefly and both its parasitoids spread to Natitingou (10°20′N, 540 km) in 1995 and Bembereke (10°14′N) in 1996, whereby E. dispersa arrived within less than a year of its host and quickly became dominant in the two localities on the northern front. In subsequent years, the parasitoids established their geographical niches, with E. dispersa being more abundant (up to 89%) in the coastal south bellow latitude 7°30′N and E. guadeloupae (up to 84%) in the north between latitudes 7°30′ and 10°30′N. We conclude that the gradual replacement observed over ten years and over 500 km has to do with longitudinal shifts in the length and severity of the dry season and the higher susceptibility to these conditions by E. dispersa.     

Northward expansion and climatic factors affecting the distribution limits of Cheilomenes sexmaculata (Coleoptera: Coccinellidae) in Japan

The distributional expansion of the ladybird beetle Cheilomenes sexmaculata (Fabricius) in Japan was analyzed based on literature surveys and observations of 1,312 individual specimens collected from 1918 to 2005. An expansion toward higher latitudes, from Kyushu (33°N) to central Honshu (36°N), was observed between 1910 and the early 1990s. Multiple regression analysis showed that the presence of this beetle was associated with an annual mean temperature but not with the mean minimum temperature in the coldest month, and 95 % occurrence probability of this beetle was obtained in a locality at 15.1 °C annual mean temperature. The northward expansion of this species synchronizes with increasing areas where an annual mean temperature is more than 15 °C. Therefore, climatic warming over the past 100 years is considered as a major factor influencing the northward expansion of this species.     

Geographic variations in life-history traits of the intertidal ocypodid crab Macrophthalmus banzai

Reproductive traits of the mud crab Macrophthalmus banzai were compared in populations from Okinawa (26°13′ N) and Amakusa (32°32′ N). Crabs matured earlier and at a smaller size in Okinawa than in Amakusa, but growth rate did not differ between the two localities. Population density was much higher in Okinawa. Breeding occurred in winter in Okinawa and in summer in Amakusa. In Okinawa, females produced one brood at over 1 year of age and then died. In Amakusa, females produced one brood at over 1 year of age, and one or two broods at around 2 years of age, and then died. Egg weight in the Okinawa population was almost twice that of the Amakusa population. Furthermore, brood weight was larger in Okinawa than in Amakusa. Longevity was 16–19 months in Okinawa and 28–30 months in Amakusa. At high latitudes, the winter low temperature blocks reproduction of M. banzai. At low temperature blocks reproduction of M. banzai. At low latitudes, their short lifespan prevents iterative breeding. Thus, the difference in breeding season greatly affects other life-history traits.     

Poleward increase in feeding efficiency of leafminer Stigmella lapponica (Lepidoptera: Nepticulidae) in a latitudinal gradient crossing a boreal forest zone

Damage to plant communities imposed by insect herbivores generally decreases from low to high latitudes. This decrease is routinely attributed to declines in herbivore abundance and/or diversity, whereas latitudinal changes in per capita food consumption remain virtually unknown. Here, we tested the hypothesis that the lifetime food consumption by a herbivore individual decreases from low to high latitudes due to a temperature-driven decrease in metabolic expenses. From 2016 to 2019, we explored latitudinal changes in multiple characteristics of linear (gallery) mines made by larvae of the pygmy moth, Stigmella lapponica, in leaves of downy birch, Betula pubescens. The mined leaves were larger than intact leaves at the southern end of our latitudinal gradient (at 60°N) but smaller than intact leaves at its northern end (at 69°N), suggesting that female oviposition preference changes with latitude. No latitudinal changes were observed in larval size, mine length or area, and in per capita food consumption, but the larval feeding efficiency (quantified as the ratio between larval size and mine size) increased with latitude. Consequently, S. lapponica larvae consumed less foliar biomass at higher latitudes than at lower latitudes to reach the same size. Based on space-for-time substitution, we suggest that climate warming will increase metabolic expenses of insect herbivores with uncertain consequences for plant–herbivore interactions.     

Different responses to cold weather in two pied flycatcher populations

We compared how breeding parameters differ according to prevailing weather conditions between a marginal, subarctic (69°N) and temperate (61°N) population of the pied flycatcher Ficedula hypoleuca, a small migratory insectivorous passerine. We predicted that the effects of weather on breeding performance (clutch size, hatching success, nestling growth, fledging success) would be greater at northern latitudes, where the weather conditions are more extreme and unpredictable. We found that the breeding parameters, except clutch size, were not, however, inferior in the north. Northern birds, unlike the southern ones, responded to colder conditions by laying smaller clutches and maintaining a larger energy reserve (indicated by higher female body mass and higher levels of subcutaneous fat). If a cold spell occurred during the nestling period, southern flycatchers had 5–10% lower fledging success than the northern ones. Our results indicate that in the north, the breeding individuals coped with cold and variable weather better than the individuals in the southern population. This could be adaptive, because at high latitudes there is a higher probability of cold weather at the time of breeding.     

Seasonal distribution of the long-nosed bat (Leptonycteris curasoae) in North America: does a generalized migration pattern really exist?

Aim This paper examines the migration of the tropical nectarivorous bat Leptonycteris curasoae considered as a latitudinal migrant that breeds in south-west United States and northern Mexico in spring and migrates southward during fall. We tested the hypothesis that the latitudinal migration occurs only locally given by the local availability of bat resources, leading to migratory movements in zones with seasonal scarcity of resources and to resident bat populations where resources are available throughout the year. Localization We analysed the presence of L. curasoae along its distribution range in North America (between 14°N and 33°N). Study cases were also conducted in three Mexican localities: the Tehuacán Valley (17°48′–18°58′N and 96°48′–97°43′W), Sonoran Desert (28°41′N and 110°15′W), and the coast of Jalisco (19°32′N and 105°07′W). Methods Geographic evidence for latitudinal migration of L. curasoae was analysed using 94-year capture records housed in twenty-two collections of North America. Records were analysed using a Geographical Information System (GIS), in which floral resources and capture records were integrated. Monthly captures in the Tehuacán Valley were conducted during three years and bats abundance and reproductive status were correlated with the phenology of bat resources. Bat captures were also conducted during two consecutive years in an extratropical desert during winter and spring, and during one spring in the coast of Jalisco. Results The latitudinal migration of L. curasoae in North America only occurs at latitudes near 30°N, whereas bats may be residents at latitudes lower than 21°N. Captures were associated always to the availability of floral resources in both geographical and local scales. Main conclusions The existence of resident populations in the tropics with two reproductive events support the hypothesis that migration only occurs in the northern distribution limit of this nectar-feeding bat.     

Abundance and diversity of birch‐feeding leafminers along latitudinal gradients in northern Europe

Latitudinal patterns in biotic interactions, including herbivory, have been widely debated during the past years. In particular, recent meta‐analysis questioned the hypothesis that herbivory increases from the poles towards the equator. Our study was designed to verify this hypothesis by exploring latitudinal patterns in abundance and diversity of birch‐feeding insect herbivores belonging to the leafminer guild in northern Europe, from 59° to 69°N. We collected branches from five mature trees of two birch species (Betula pendula and B. pubescens) at each study site (ten sites for each of five latitudinal gradients) twice per season (in early and late summer of 2008–2011) and attributed all mines found on leaves of these branches to a certain taxon of insects. Latitudinal patterns were quantified by calculating Spearman rank correlation coefficients between both abundance and diversity of leafmining taxa and latitudes of sampling sites. In general, both abundance and diversity of leafminers significantly decreased with latitude. However, we discovered pronounced variation in patterns of latitudinal changes among study years and leafminer taxa. Variation among study years was best explained by mean temperatures in July at the northern ends of our gradients. During cold years, abundance of leafminers significantly decreased with latitude, while during warm years the abundance was either independent of latitude or even increased towards the pole. In the northern boreal forests (66° to 69°N), herbivores demonstrated larger changes in densities in response to temperature variations than in the boreo‐nemoral forests (59° to 62°N). Our data suggest that climate warming will result in a stronger increase in herbivory at higher latitudes than at lower latitudes.     

Latitudinal variation in photoperiodic response of the three‐spined stickleback Gasterosteus aculeatus in western North America

Reproductive maturation in both male and female three‐spined stickleback Gasterosteus aculeatus was strongly photoperiodic in a northern population (Alaska, 61° N) but not in a southern population (Oregon, 43° N) from western North America. Increasing reliance on photoperiod with increasing latitude is a general phenomenon among vertebrates, and is probably due to the anticipation of a narrower window of opportunity for reproduction and development at higher latitudes.     

MORPHOLOGICAL VARIATION AND DEVELOPMENT IN RAMALINA MENZIESII TAYL.

The common west coast lichen Ramalina menziesii Tayl. has been studied in an attempt to determine the extent of morphological variation and to understand the factors that determine its form. An analysis of a typical population near Santa Barbara, CA, suggested that intrapopulation variation in form was controlled primarily by size increase during growth. Test populations obtained from latitudes as far north as 54°N and as far south as 28°N had values for various morphological characters that were very similar to the Santa Barbara population. It is concluded that variation in form may be the result of differential rates of growth and possibly varying frequency of environmental stresses which disintegrate the thallus.     

SEED MORTALITY IN DAUCUS CAROTA POPULATIONS: LATITUDINAL EFFECTS

Daucus carota, a common herbaceous weed, grows over a wide latitudinal range in eastern North America. Viability and germination tests of mature seeds collected from 36° to 45°N were conducted to measure predispersal seed mortality. Viability and germination declined as latitude of the seed source decreased. Only 30–50% of the seeds from southern populations germinated owing to high embryo inviability and absence of embryos. Sixty to ninety percent of the seeds from northern populations germinated. Reciprocal planting of seeds in outdoor experimental plots at three latitudes and testing of seeds over two generations together showed that the environment in which seeds mature, rather than environmental preconditioning over generations or genetically-based differences among populations, explain this variation in germination ability. Within-latitude germination declined in experimental plots as population age of the seed source within latitudes increased. The data indicate that predispersal seed mortality can influence local population persistence and that seed mortality is an increasingly important factor in population regulation at the southern limit of the species’ range.     

Global distribution of fin whales Balaenoptera physalus in the post‐whaling era (1980–2012)

相似文献   

Geographical variations of elytral color polymorphism in Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae)

The geographical variation in elytral color polymorphism in Cheilomenes sexmaculata (Fabricius) was analyzed based on data from specimen surveys. In all, 1549 individuals collected from different latitudes throughout Indonesia to Japan were categorized into 20 morph types of elytra. Results show that the morph types have a geographical cline: dark types increased with latitude, although the light types showed higher relative frequency in lower latitudes, which suggests that the geographic variation in elytral color polymorphism in C. sexmaculata is a product of selection by climate. The darker morph types might be advantageously able to make fuller use of insolation at higher latitudes, whereas the lighter morph types were likely to reduce heat stress at lower latitudes. In most areas across Southeast and South Asia, all specimens were of the lightest type, which may imply either: (i) the saturation of genes expressing light morph types, which have less solar absorption, due to tropical climate; or (ii) an enhanced warning function of bright red against predators. On Miyako Island of Japan, a unique frequency of morph types was found compared to the adjacent areas.     

Latitudinal variation in growth and survival of juvenile corals in the West and South Pacific

Reef-building corals are found across > 30° of latitude from tropical to temperate regions, where they occupy habitats greatly differing in seawater temperature and light regimes. It remains largely unknown, however, how the demography of corals differs across this gradient of environmental conditions. Variation in coral growth is especially important to coral populations, because aspects of coral demography are dependent on colony size, with both fecundity and survivorship increasing with larger colonies. Here we tested for latitudinal variation in annual growth rate and survival of juvenile corals, using 11 study locations extending from 17° S to 33° N in the West and South Pacific. Regression analyses revealed a significant decline in annual growth rates with increasing latitude, whereas no significant latitudinal pattern was detected in annual survival. Seawater temperature showed a significant and positive association with annual growth rates. Growth rates varied among the four common genera, allowing them to be ranked Acropora > Pocillopora > Porites > Dipsastraea. Acropora and Pocillopora showed more variation in growth rates across latitudes than Porites and Dipsastraea. Although the present data have limitations with regard to difference in depths, survey periods, and replication among locations, they provide evidence that a higher capacity for growth of individual colonies may facilitate population growth, and hence population recovery following disturbances, at lower latitudes. These trends are likely to be best developed in Acropora and Pocillopora, which have high rates of colony growth.

     

Effects of population density and female body mass on litter size in European roe deer at a continental scale

Roe deer (Capreolus capreolus) has a wide distributional range in Europe and inhabits a broad range of habitats and environmental conditions. Thus, populations of roe deer show substantial variation in demographic parameters. We aimed to determine whether body mass and population density—which influence the reproductive potential of roe deer at a local scale—affect their reproductive potential at a biogeographical scale as well. We reviewed the literature (covering years 1948–2015) on in utero litter size in roe deer from 59 locations in 14 countries in Europe. Across study sites, mean litter size varied from 1.0 to 2.4 embryo or corpora lutea per female, and population density ranged from 4.5 to 73.5 individuals/km². Mean body mass varied from 11.2 to 20.8 kg in subadult females and from 12.1 to 22.4 kg in adult females. Between 46° and 56° N, body mass of females did not show a significant trend of increase, whereas between 56° and 63° N, it increased with latitude (Bergmann’s rule). We used linear mixed-effects models (LMMs) to analyse the influence of body mass and population density (analysed separately) on litter size. Females with larger body mass produced larger litters, and this pattern was pronounced at both higher and lower latitudes. Higher population densities negatively affected litter size in a sample of all females. This macroecological analysis showed that factors influencing the reproductive potential of roe deer females at local scales produce similar effects at the biogeographical scale.     

Past and present distribution of the North African–Asian lion subgroup: a review

• 1 The North African–Asian lion subgroup, which is composed of two subspecies, the Barbary lion, Panthera leo leo, and the Asian lion, P. l. persica, was nearly exterminated during the last centuries. The remaining free‐ranging population of Asian lions consists of c. 350 animals in India. The Barbary lion subsists as captive animals in zoos or circuses, all of which originate from the Moroccan Royal Collection. There have been multiple genetic hybridizations with sub‐Saharan lions.
• 2 Several incomplete distribution maps of the past occupation of lions were proposed in the literature. I examine the distribution of these lions with the help of a larger database, extracted from zoological, archaeological and historical reports. Some records are however not completely reliable. Data were collected over a long period of time (from the Epipaleolithic to the modern times) in Eurasia, North Africa and the Arabian Peninsula.
• 3 Dispersal took place in latitudes as far south as 15°N (Yemen) to 18°N (Mali; Chad) and as far north as 45–48°N (Bulgaria); and to longitudes as far west as 5.57°W (Morocco) and as far east as 84°E (India). Expansion was probably constrained by natural ecological factors northwards (higher seasonality, harsher winters) and southwards (extension of aridity after 3000 BP). At latitudes between 40 and 43°N, lions seem to have become a permanent part of the fauna during 6–8 millennia.
• 4 Lions were brought to extinction by humans through hunting, captures for exhibition in zoos and by the associated natural fragmentation of wild populations. The dates at which extinction took place varied greatly according to the geographical sites: 3000 BC for temperate Europe; 1000 BC in the south of Greece; 12–13th century in the Near East, Arabian Peninsula, Trans‐Caucasia or north of Afghanistan; and 19–20th century for North Africa, the Middle East and India.

     

Growth dynamics and transcriptional responses of a Red Sea Prochlorococcus strain to varying temperatures

Prochlorococcus play a crucial role in the ocean's biogeochemical cycling, but it remains controversial how they will respond to global warming. Here we assessed the response to temperature (22–30°C) of the growth dynamics and gene expression profiles of a Red Sea Prochlorococcus strain (RSP50) in a non-axenic culture. Both the specific growth rate (0.55–0.80 day⁻¹) and cell size (0.04–0.07 μm³) of Prochlorococcus increased significantly with temperature. The primary production released extracellularly ranged from 20% to 34%, with humic-like fluorescent compounds increasing up to fivefold as Prochlorococcus reached its maximum abundance. At 30°C, genes involved in carbon fixation such as CsoS2 and CsoS3 and photosynthetic electron transport including PTOX were downregulated, suggesting a cellular homeostasis and energy saving mechanism response. In contrast, PTOX was found upregulated at 22°C and 24°C. Similar results were found for transaldolase, related to carbon metabolism, and citrate synthase, an important enzyme in the TCA cycle. Our data suggest that in spite of the currently warm temperatures of the Red Sea, Prochlorococcus can modulate its gene expression profiles to permit growth at temperatures lower than its optimum temperature (28°C) but is unable to cope with temperatures exceeding 30°C.     

Phylogeography of Trochodendron aralioides (Trochodendraceae) in Taiwan and its adjacent areas

Aim This paper described current phylogeographical patterns of chloroplastic DNA variation of Trochodendron aralioides, a temperate tree species, and inferred its possible refugium in Taiwan. This information was compared with the known phylogeographical pattern of subtropical tree species. Location A total of 24 populations were sampled including 20 from Taiwan, two each from the Ryukyus and Japan. Methods A haplotype network was constructed by computer program TCS, various parameters of genetic diversity were calculated and neutrality was tested by computer program DnaSP. To examine the similarity of genetic structure among populations, a maximum parsimony tree was reconstructed by computer program PAUP*. The results of isozyme of T. aralioides from a previous publication were incorporated into this study to infer the phylogeographical history. Results Nine haplotypes according to six substitutions, two indels and one inversion of the two cpDNA intergenic spacer fragments (petG‐trnP and petA‐psbJ) of T. aralioides were recognized. Genetic structure of the population of Japan is totally different from those of Taiwan and the Ryukyus. In Taiwan, the genetic structure was differentiated among populations revealed by G_st = 0.700 and N_st = 0.542, and the population genetics was clearly spatially structured. Two population groups were recognized. The first group was distributed islandwide and extended to the Ryukyus. The second group contained five of the seven known haplotypes, and was restricted to the area between latitude 24°46′ and 24°06′ N. Conclusions In Taiwan, north‐central area between latitude 24°46′ and 24°06′ N is potentially a refugium during the last glaciations. This finding is contradicted to subtropical species as Cyclobalanopsis glauca.     

Length–weight relationships of three fish species from Kerala waters,south‐west coast of India

Length–weight relationships (LWRs) of three fish species: Scomberomorus commerson, Alepes vari, and A. kleinii were estimated from Kerala waters, south‐west coast of India. Fish were captured between June 2016 and June 2017 by various gears such as ring seine (8–26 mm mesh size), trawl (30–40 mm cod end mesh size), hook and line (hook number VI–XII), smaller mesh sized drift gill net (26–90 mm) and larger one (120–170 mm) for bigger size fishes. Fish were collected on weekly basis from Cochin Fisheries Harbour (Lat. 09°56′327″N, Long. 76°15′764″E), Munambam Fisheries Harbour (Lat. 10°10′965″N, Long. 76°10′258″E), Kalamukku (Lat. 09°59′924″N, Long. 76°14′564″E) and Chellanam (Lat. 09°47′950″N, Long. 76°16′551″E). All LWRs were significant with r² values ranged from 0.944 to 0.996 and b values ranged from 2.722 to 3.021 (p < .001). In addition, this study provides the information on LWRs and new maximum size for Alepes vari and A. kleinii.