Cathemerality in the mongoose lemur, Eulemur mongoz

Results of a 10 month study of the mongoose lemur (Eulemur mongoz) at Anjamena are presented. The activity pattern is documented in detail for both wet and dry seasons based on observations conducted over the entire 24 h period. E. mongoz was found to be cathemeral throughout the year but exhibited shifts towards more diurnal activity in the wet season and more nocturnal activity in the dry season. The cathemeral activity pattern in the mongoose lemur appears to be coordinated with sunrise, sunset, and day length and modulated by an inhibitory effect of low nocturnal light intensity in the forest during the wet season, resulting in mainly diurnal activity. Temperature and rainfall may also influence the activity pattern. Few advantages to food-related behavior appear to derive from this activity pattern, although resource accessibility may be enhanced by nocturnal behavior in the dry season, leading to reduction in interspecific competition. Cathemerality may also represent a behavioral thermoregulatory mechanism allowing the mongoose lemur to conserve energy by being active during the cool nights of the dry season. In addition, nocturnal behavior in the dry season probably allows avoidance of predation by raptors at the time of year when least protection is afforded by vegetation.     

Surveys of sympatric lemurs at Anjamena, north-west Madagascar

In order to assess the status of lemurs along the lower reaches of the Mahavavy in north-west Madagascar, we carried out transect line sampling at Anjamena between April and August 1995. These data were complemented by additional absence–presence surveys conducted in 1994 and 1995 in many of the remaining forested areas of the region. This is the first study of lemur population density estimates for the faunal subregion between the rivers Mahavavy and Betisboka. Six sympatric lemurs are found at Anjamena: Cheirogaleus medius, Eulemur fulvus rufus, E. mongoz, Lepilemur sp., Microcebus murinus and Propithecus verreauxi coronatus. Data suggest that in some parts of the region large numbers of lemurs may still be found (E. f. rufus 121 individuals per km², E. mongoz (45), Lepilemur sp. (110), M. murinus (85) and P. v. coronatus (173)). No density data are provided for C. medius. In conclusion, as high lemur population densities may still be found and, in particular, P. v. coronatus is not known to exist in any protected area, Anjamena could serve as an important addition to the protected area system of north-west Madagascar.     

Group Size, Home Range Use, and Seasonal Variation in the Ecology of Eulemur mongoz

We collected data during a 10-month study carried out on the mongoose lemur, Eulemur mongoz, at Anjamena in northwestern Madagascar, which provide baseline information on seasonal variation in the ecology, home range use and some aspects of the behavior of two neighboring groups. We monitored group size of nine groups in the study area and assessed them for seasonal variation. We present additional information collected during short-term surveys in other areas before and during the study for comparison. The study groups were small family units, and changes in group size were limited to births and emigrations of sexually mature progeny. In spite of clear seasonal changes in climate and vegetation, there is no variation in grouping patterns, so it is not possible to correlate variation in group size with seasonal variation of ecological variables. Comparison with ecological data from other field studies on lemurids reveals differences in food resource distribution in western forests versus other types of Malagasy forest. This distribution of food resources may predict home range size in mixed frugivorous–folivorous lemurs. Small home ranges, mainly in the West, could be correlated with a uniform distribution of food resources. Finally, we suggest that the dry season in the West may not present frugivorous–folivorous lemurs with major problems in finding an adequate food supply. This is supported by the lack of seasonal differences in ranging behavior of mongoose lemurs.     

Isolation of 10 microsatellite markers for mongoose lemurs (Eulemur mongoz)

We present here 10 new microsatellite markers for the mongoose lemur (Eulemur mongoz), nine of which were isolated from E. mongoz and one from Lemur catta. At least 60 individuals were genotyped for each of the 10 loci. Mendelian inheritance at each locus was tested by genotyping five captive families with known pedigrees. All loci were polymorphic and demonstrated simple Mendelian inheritance. The microsatellite markers presented here will be useful for genetic surveys of wild E. mongoz, to gain insights into the genetic background of the captive population, and to aid in the conservation of the species’ genetic diversity.     

Ecological correlates to activity and habitat use of two prosimian primates: Eulemur rubriventer and Eulemur fulvus rufus in Madagascar

In this paper, I provide data on the possible effects of group size and seasonal changes in food availability on the activity and habitat use patterns of two species of prosimian primate: the rufous lemur (Eulemur fulvus rufus) and the red-bellied lemur (Eulemur rubriventer). General and subtle seasonal differences were observed between lemur species in (1) group size and composition, (2) activity profiles, and (3) habitat use. Rufous lemur groups were larger (mean = 8 individuals) and contained more adults than red-bellied lemur groups (mean = 3 individuals). The overall degree and distribution of diurnal activity differed between lemur species and varied within species with seasonal changes in food availability. In general, rufous lemurs traveled more often than red-bellied lemurs. During food scarcity, both species increased the amount of time spent feeding, although peak feeding and traveling times differed. Both species also preferred horizontal substrates; however, during food scarcity, red-bellied lemurs used terminal branches more often while feeding than rufous lemurs. In addition, red-bellied lemurs used the lower middle story forest and rested in taller, upper canopy trees more often than rufous lemurs. Differences in activity and habitat use patterns between lemur species were more related to seasonal changes in food availability than overall differences in group size. These behavioral patterns may represent different strategies used by each lemur species to avoid directly competing for similar resources during times of food scarcity. © 1996 Wiley-Liss, Inc.     

Diet and nutrition in wild mongoose lemurs (Eulemur mongoz) and their implications for the evolution of female dominance and small group size in lemurs

Data collected on the feeding behavior, food intake, and chemical analyses of plant foods were used to document seasonal variation in diet and nutrition in Eulemur mongoz in northwestern Madagascar. E. mongoz conforms to the general Eulemur dietary pattern, with a predominantly frugivorous diet supplemented mainly by leaves, flowers, and nectar. Phytochemical analysis revealed high water contents in all the main plant foods; mature fruit and flowers contained the most water-soluble carbohydrates; immature leaves were richest in protein and essential amino acids; the limiting amino acids in all plant foods were methionine and cystine; ash (mineral) content was highest in petioles and mature leaves; crude lipid content was highest in seeds; and crude fiber content was indistinguishable between immature and mature fruit and leaves. High-fiber foods were eaten during both seasons; the wet season diet was dominated by high-energy foods (mature fruit, nectar, and seeds), while the dry season diet contained foods high in energy (mature fruit and flowers) and high in protein (immature leaves) and minerals (mature leaves and petioles). However, nutrient intake did not vary between seasons, implying that nutrient requirements are met throughout the year. These results suggest we draw more conservative conclusions when interpreting dietary variability in the absence of chemical analysis, and also draw into question the idea that nutritional stress is a factor in the timing of reproduction in lemurs and, by extension, is linked to the prevalence of female dominance and small group size in lemurs.     

DETERMINANTS OF PRIMATE SOCIAL ORGANIZATION: COMPARATIVE EVIDENCE AND NEW INSIGHTS FROM MALAGASY LEMURS

The aim of this review is to summarize newly available information on lemur social systems, to contrast it with the social organization of other primates and to relate it to existing models of primate social evolution. Because of their evolutionary history, the primates of Madagascar constitute a natural experiment in social evolution. During millions of years of isolation, they converged with other primates only in the most fundamental way in the evolution of solitary, pair-living and group-living species, but deviate in several respects within these basic categories of social organization. Solitary lemurs remain poorly studied, but their social organization appears to be broadly similar to that of other solitary primates, even though the unexpected lack of sexual dimorphism may indicate that similar types of social organization can give rise to different mating systems. The determinants of a solitary lifestyle remain elusive. Pair-living lemurs show striking convergences with other monogamous primates in several behavioural traits, but also deviate in that the majority of species are at least partly nocturnal and do not exhibit direct paternal care of dependent young. Group-living lemurs have not evolved single-male groups, male-bonded and multi-level societies, and polyandrous groups may also be lacking. Female philopatry is common, but female bonds are generally weakly developed and eviction of females from natal groups is not unusual. Group-living lemurs also differ from anthropoids in that their groups have even adult sex ratios, smaller average size and may split up on a seasonal basis. Feeding competition, predation risk and reproductive competition can not fully explain these unusual aspects of lemur social organization. It has therefore been suggested that the social consequences of the risk of infanticide and of recent changes in activity may be ultimately responsible for these idiosyncracies of group-living lemurs, an explanation largely supported by the available evidence. Thus, social factors and fundamental life-history traits, in addition to ecological factors, contribute importantly to variation in social systems among lemurs, and possibly other primates. However, neither the diversity of lemur social systems, nor the evolutionary forces and mechanisms operating in these and other primates are yet fully understood.     

Evolutionary history inferred from the de novo assembly of a nonmodel organism,the blue‐eyed black lemur

Lemurs, the living primates most distantly related to humans, demonstrate incredible diversity in behaviour, life history patterns and adaptive traits. Although many lemur species are endangered within their native Madagascar, there is no high‐quality genome assembly from this taxon, limiting population and conservation genetic studies. One critically endangered lemur is the blue‐eyed black lemur Eulemur flavifrons. This species is fixed for blue irises, a convergent trait that evolved at least four times in primates and was subject to positive selection in humans, where 5′ regulatory variation of OCA2 explains most of the brown/blue eye colour differences. We built a de novo genome assembly for E. flavifrons, providing the most complete lemur genome to date, and a high confidence consensus sequence for close sister species E. macaco, the (brown‐eyed) black lemur. From diversity and divergence patterns across the genomes, we estimated a recent split time of the two species (160 Kya) and temporal fluctuations in effective population sizes that accord with known environmental changes. By looking for regions of unusually low diversity, we identified potential signals of directional selection in E. flavifrons at MITF, a melanocyte development gene that regulates OCA2 and has previously been associated with variation in human iris colour, as well as at several other genes involved in melanin biosynthesis in mammals. Our study thus illustrates how whole‐genome sequencing of a few individuals can illuminate the demographic and selection history of nonmodel species.     

Seasonal changes in general activity, body mass and reproduction of two small nocturnal primates: a comparison of the golden brown mouse lemur ( Microcebus ravelobensis) in Northwestern Madagascar and the brown mouse lemur ( Microcebus rufus) in Eastern Madagascar

To investigate for the first time the relationship between contrasting patterns of seasonal changes of the environment and activity, body mass and reproduction for small nocturnal primates in nature, we compared a population of golden brown mouse lemur (Microcebus ravelobensis) in a dry deciduous forest of northwestern Madagascar and of the brown mouse lemur (Microcebus rufus) in an evergreen rain forest of eastern Madagascar. Both species live under similar photoperiodic conditions. Golden brown mouse lemurs (GBML) were active during the whole period (May to December) irrespective of changing environmental conditions. In contrast, a part of the population of brown mouse lemurs (BML) showed prolonged seasonal torpor, related to body mass during periods of short day length and low ambient temperatures. Differences between species might be due to differences in ambient temperature and food supply. Body weight and tail thickness (adipose tissue reserve) did not show prominent differences between short and long photoperiods in GBML, whereas both differ significantly in BML, suggesting species-specific differences in the photoperiodically driven control of metabolism. Both species showed a seasonal reproduction. The rate of growth and size of the testes were similar and preceded estrous onset in both species suggesting a photoperiodic control of reproduction in males. The estrous onset in females occurred earlier in GBML than in BML. Estrous females were observed over at least 4 months in the former, but in only 1 month in the latter species. Intraspecific variation of estrous onset in GBML may be explained by body mass. Interspecific variation of female reproduction indicates species-specific differences in the control of reproduction. Thus, environmentally related differences in annual rhythms between closely related small nocturnal lemurs emerged that allow them to cope with contrasting patterns of seasonal changes in their habitats.     

Similarities,differences, and seasonal patterns in the diets ofEulemur rubriventer andEulemur fulvus rufus in the Ranomafana National Park,Madagascar

I studied the diets of two sympatric species ofEulemur (E. fulvus rufus andE. rubriventer) in the Ranomafana National Part in southeastern Madagascar from July 1988 through August 1989. Both species were highly frugivorous throughout the year and devoted similar amounts of time to feeding daily; the composition of their diets were similar. Three aspects of both lemur species' diets were correlated with seasonal food availability: changes in interspecific dietary overlap, the length of feeding bouts, and the amount of time devoted to feeding daily. Throughout the year neither species had a more diverse or more folivorous diet than its sympatric congener. However, there were several consistent year-round differences between their diets.E. f. rufus initiated more feeding bouts daily that were shorter in duration than those ofE. rubriventer. E. f. rufus also consistently exploited more unripe fruits and mature leaves thanE. rubriventer did throughout the study.E. f. rufus migrated from the study site during a period of fruit scarcity. These dietary patterns are discussed here in regard to feeding patterns observed in other sympatric congeneric primate species, whether these dietary differences can contribute to these two species' ability to coexist, and how differences in diet may be influenced by differences in social structure. I suggest that subtle, consistent differences in diet and seasonal dietary differences are sufficient to allow these two species to coexist.     

Female dominance in Indri indri.

A total of 15 months were spent on field research in eastern Madagascar studying the largest extant lemur Indri indri. Social relationships were analysed according to the frequency and direction of affiliative and agonistic behaviours, and with respect to the relative tree positions and behavioural synchrony of group members. The relationship between the adult male and adult female in each group was distinguished by the subordinance of the former. Between group variation in adults' relationships are examined with respect to the function of this behaviour.     

Seasonal and diel activity of Ixodes ricinus (Acari: Ixodidae) subpopulations in Denmark. Aspects of size, physiological age, and malate dehydrogenase genotype in a forest site without any undergrowth

The underlying population dynamics and the behavioural patterns of the vectors are key issues in understanding the transmission of vector borne pathogens. For the tick Ixodes ricinus both seasonal and diel activity have been described as bimodal patterns, which in seasonal aspect has been interpreted as representing two cohorts. However, recent studies have shown that this interpretation may be incorrect. The aim of this study was to obtain more detailed information on nymph host seeking by studying subpopulations of ticks during the day and season. The study was designed to allow for comparisons of the diel variation and seasonal variation in their dependency in a number of tick characteristics. The study took place in a forest with planted beech trees without any undergrowth. Ticks were collected by flagging the dead leaves on the forest floor. For each nymph, a number of visual observations were made. The size and physiological age was observed and the nymphs were genotyped in the malate dehydrogenase locus (MDH, E.C. 1.1.1.37). Briefly the main results can be given as: (i) There were significant differences in the composition of size classes during the season, but only limited trends in time. (ii) The proportion of the small nymphs was highly variable, with a variation from 3% to 24% in October and September, respectively. (iii) The diel variation in MDH genotypes was significant in May and August. (iv) Nymph size classes and physiological age appeared to interact. The non-random interaction was caused by a relatively even distribution of small nymphs in all four age classes, while large nymphs tended to fall into age class 2 and 3. The length by age interaction for the individual months was noted to be significant in May, July, August and September, but not in June. Similarly the interaction was significant in the morning and afternoon, but not at midday. The overall results describe the seasonal and diel activity patterns as changing systematically for several characteristics under the influence of weather condition and population dynamics. In conclusion: The observations are best interpreted as being produced of a single cohort of ticks, but the revealed complexity of the host seeking activity suggest that measures of activity x abundance should be interpreted very cautiously in relation to population dynamics.     

Reproduction in Coquerel's dwarf lemur (Mirza coquereli)

Most nocturnal Malagasy primates, as well as many diurnal species, are highly endangered in their natural habitat. Captive breeding programs have been established for many species, but detailed information on reproduction is only available for three nocturnal taxa: the mouse lemur (Microcebus murinus), the dwarf lemur (Cheirogaleus medius), and the greater dwarf lemur (Cheirogaleus major). In this study, we present data for another nocturnal Malagasy primate, Coquerel's dwarf lemur (Mirza coquereli), which has been propagated since 1982 at the Duke University Primate Center. Unlike all other Malagasy primates bred in captivity, M. coquereli cycles throughout the year, and is clearly less seasonal in its birth distribution than is C. medius or M. murinus. Estrous intervals ranged between 19 and 30.5 days. Estrus lasted no longer than 1 day. After an average gestation length of 89.2 days, litters of one or two were born. Females cycled for the first time between 8 and 15 months of age, and gave birth for the first time between 12.8 and 33.5 months of age. The earliest mating of a male leading to conception was observed at the age of 17 months. For males and females, an increase in daylength appears to trigger pubertal development. Males had seasonal changes in testicular volume which were not explained by covariation with body weight. Maximum testis size occurred in spring, when breeding activity was highest. The occurrence of year-round reproduction in M. coquereli, and the absence of seasonal fattening and/or hibernation, along with their specialized winter diet, may be correlated. © 1995 Wiley-Liss, Inc.     

Sex and seasonal differences in aggression and steroid secretion in Lemur catta: are socially dominant females hormonally 'masculinized'?

Female social dominance characterizes many strepsirrhine primates endemic to Madagascar, but currently there is no comprehensive explanation for how or why female lemurs routinely dominate males. Reconstructing the evolutionary pressures that may have shaped female dominance depends on better understanding the mechanism of inheritance, variation in trait expression, and correlating variables. Indeed, relative to males, many female lemurs also display delayed puberty, size monomorphism, and 'masculinized' external genitalia. As in the spotted hyena (Crocuta crocuta), a species characterized by extreme masculinization of the female, this array of traits focuses attention on the role of androgens in female development. Consequently, I examined endocrine profiles and social interaction in the ringtailed lemur (Lemur catta) to search for a potential source of circulating androgen in adult females and an endocrine correlate of female dominance or its proxy, aggression. I measured serum androstenedione (A(4)), testosterone (T), and estradiol (E(2)) in reproductively intact, adult lemurs (10 females; 12 males) over four annual cycles. Whereas T concentrations in males far exceeded those in females, A(4) concentrations were only slightly greater in males than in females. In both sexes, A(4) and T were positively correlated, implicating the Delta(4)-biosynthetic pathway. Moreover, seasonal changes in reproductive function in both sexes coincided with seasonal changes in behavior, with A(4) and T in males versus A(4) and E(2) in females increasing during periods marked by heightened aggression. Therefore, A(4) and/or E(2) may be potentially important steroidal sources in female lemurs that could modulate aggression and underlie a suite of masculinized features.     

Morphological characterization of a brown lemur hybrid zone (Eulemur rufifrons × E. cinereiceps)

Hybridization has recently been identified as a pervasive force in the evolution of primates. In this study, we characterized a hybrid zone between two species of brown lemur (Eulemur rufifrons and E. cinereiceps) in the Andringitra region of southeastern Madagascar using morphological traits. We immobilized animals along a north-south transect (～80 km), scored them for their degree of hybridity using pelage traits and measured standard morphometric variables. Results from our study suggest that hybridization between E. rufifrons and E. cinereiceps is extensive, with the hybrid zone extending over 42.6 km and being composed mostly of later generation hybrids. We also identified significant variation between ancestral groups in our study: hybrid males exhibited longer tails than both parental species and sexual dimorphism in upper canine height favoring males was documented in E. rufifrons. These patterns could suggest that gene flow between parental and hybrid populations is relatively limited. Finally, significant differences between ancestral groups in relative body mass and skin-fold thickness were absent in our study, indicating that, as measured by these proxies, hybrids are equally as fit as parental forms. Based on these preliminary findings, the Andringitra hybrid zone could conform to the bounded superiority model of hybrid zone stability (i.e., it could be being maintained by selection favoring hybrids within transitional habitats). Accordingly, hybrids in Andringitra may be an unusual case among primates, representing a stable recombinant but distinct lineage. This conclusion has important implications for evolutionary processes within the brown lemur species complex.     

Seasonal and diel activity of Ixodes ricinus (Acari: Ixodidae) subpopulations in Denmark. Aspects of size, physiological age, and malate dehydrogenase genotype in a forest site without any undergrowth

The underlying population dynamics and the behavioural patterns of the vectors are key issues in understanding the transmission of vector borne pathogens. For the tick Ixodes ricinus both seasonal and diel activity have been described as bimodal patterns, which in seasonal aspect has been interpreted as representing two cohorts. However, recent studies have shown that this interpretation may be incorrect. The aim of this study was to obtain more detailed information on nymph host seeking by studying subpopulations of ticks during the day and season. The study was designed to allow for comparisons of the diel variation and seasonal variation in their dependency in a number of tick characteristics. The study took place in a forest with planted beech trees without any undergrowth. Ticks were collected by flagging the dead leaves on the forest floor. For each nymph, a number of visual observations were made. The size and physiological age was observed and the nymphs were genotyped in the malate dehydrogenase locus (MDH, E.C. 1.1.1.37). Briefly the main results can be given as: (i) There were significant differences in the composition of size classes during the season, but only limited trends in time. (ii) The proportion of the small nymphs was highly variable, with a variation from 3% to 24% in October and September, respectively. (iii) The diel variation in MDH genotypes was significant in May and August. (iv) Nymph size classes and physiological age appeared to interact. The non-random interaction was caused by a relatively even distribution of small nymphs in all four age classes, while large nymphs tended to fall into age class 2 and 3. The length by age interaction for the individual months was noted to be significant in May, July, August and September, but not in June. Similarly the interaction was significant in the morning and afternoon, but not at midday. The overall results describe the seasonal and diel activity patterns as changing systematically for several characteristics under the influence of weather condition and population dynamics. In conclusion: The observations are best interpreted as being produced of a single cohort of ticks, but the revealed complexity of the host seeking activity suggest that measures of activity × abundance should be interpreted very cautiously in relation to population dynamics. This revised version was published online in July 2006 with corrections to the Cover Date.     

Locomotor activity rhythm of Talitrus saltator (Crustacea,Amphipoda) on a progradating sandy beach

In the Maremma Natural Park (Grosseto, Italy), the Collelungo beach exhibits a clear morphodynamics gradient, resulting in a severe erosion to a gradual accretion along the shoreline. Here, three sub-populations of the sandhopper Talitrus saltator (Montagu) (Crustacea, Amphipoda) were studied to highlight eventual intra- and inter-population variation of the endogenous locomotor rhythm. Individual activity recordings were carried out for 21 days in constant darkness and controlled temperature and humidity conditions. The variation of the free-running period was analysed at individual and sub-population levels, and the dependence on intrinsic (individual features) and extrinsic (habitat of origin and season) factors was analysed. A seasonal variation was highlighted, related to the seasonal spontaneous activity of the species. In summer and autumn, a significant correlation between the behavioural variation in the sub-populations (period and definition of the period) and beach physical parameters (slope and width) defined the dependence of the behavioural gradient on the environmental gradient. The observed relationship may represent an adaptation to the local coastline dynamics, suggesting the importance of a plastic behaviour as adaptive response to a variable environment.     

Environmental and social determinants of sexual function in the male lesser mouse lemur (Microcebus murinus).

Environmental factors that regulate the sexual activity of male lesser mouse lemurs have been studied experimentally with more than 60 captive animals over an 8-year period. In this nocturnal Malagasy prosimian, variation in day length is the primary factor controlling seasonal sexual activity. Plasma testosterone concentrations were low (= 9 ng/ml) during short days and reached 60 ng/ml during long days (> 12-hour day). This cyclic pattern persists unchanged when artificial photoperiodic rhythms are applied and is not altered by ageing. The timing of puberty is also regulated by photoperiodic changes. Nevertheless, the sexual activity of the male lesser mouse lemur can be dramatically modified by the social environment. In heterosexual groups, behavioural and physiological components of sexual activity are depressed in all males except the dominant one, whose aggressive interactions are always successful. Intermale sexual inhibition was shown to be mediated by chemical cues present in the urine of dominant or isolated males but not in urine of subordinate individuals. The inhibitory signals possess lipophilic properties and are not contingent on the gonadal activity of the urine donor but are linked to adrenocortical activity. By contrast, chemical signals stimulating the reproductive function of all males are found in the urine of females, the presence of which is required for the establishment of clear dominance among grouped males. Endocrine mechanisms underlying intermale sexual inhibition by chemical cues were analysed. Variations in prolactin strongly suggest that olfaction interacts with the photoperiodic regulation of reproductive function, leading to changes in the sensitivity of the negative feedback effect of testosterone on gonadotrophin secretion. Inhibitory or stimulatory effects of chemical signals are discussed in the context of their functional significance for wild populations.     

Hyperparasitism and seasonal patterns of parasitism as potential causes of low top-down control in Euproctis chrysorrhoea L. (Lymantriidae)

Pest suppression is an important ecosystem service provided by biodiversity, though antagonistic interactions may jeopardize its impact on pest suppression. Hyperparasitoids may release herbivore populations from natural enemy pressure and lead to outbreaks directly due to parasitism as well as indirect through behavioural interference. In a previous study we reported that in native populations of Euproctis chrysorrhoea L. (Lymantriidae) primary parasitism was very low and outbreaks were more likely in coastal habitats than inland. Here we hypothesise that hyperparasitoids are the underlying cause of such patterns by reporting data on direct hyperparasitism rates as well as seasonal patterns of parasitoid attack. Of the 17 primary parasitoids attacking E. chrysorrhoea, three were found to be hyperparasitized. Hyperparasitoids attack the most important E. chrysorrhoea primary parasitoids which may explain the pattern of moth density in some habitats. Seasonal patterns of parasitoids attack and flight also help to understand antagonistic interactions among E. chrysorrhoea parasitoids. We discuss the implications of our work in the context of pest control in diverse ecosystems.     

Effects of Transect Selection and Seasonality on Lemur Density Estimates in Southeastern Madagascar

I investigated how transect type (trails vs. cut transects) and seasonality influenced density estimates for 5 lemur taxa (Avahi laniger, Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus) in the Vohibola III Classified Forest in SE Madagascar. I surveyed tree height and diameter and lemur populations from June 1 to December 28, 2004 along 2 1250-m trails local people used and 2 1250-m transects cut parallel to the trails in primary rain forest. Despite dendrometric variations within and between trails and transects, only density estimates of Hapalemur griseus griseus differed significantly by transect type. The spatial variation may be a result of removal by local people of giant bamboo, which is the main food for Hapalemur griseus griseus, along trails. Conversely, seasonality influenced density estimates for Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus. The temporal variations may be related to seasonal torpor for Cheirogaleus major and increased detection probabilities during periods of fruit exploitation for Eulemur rubriventer, Microcebus rufus, and Hapalemur griseus griseus. Transect type and seasonality did not affect density estimates for Avahi laniger, which may be related to the highly folivorous and low-energy diet of the nocturnal lemur. Researchers surveying lemurs along line transects should be aware that transect selection may influence density estimates for Hapalemur griseus griseus and that seasonality may influence density estimates for Cheirogaleus major, Eulemur rubriventer, Hapalemur griseus griseus, and Microcebus rufus.