Southwestern Madagascar Research Articles

Seasonal patterns of male affiliation in ring-tailed lemurs (Lemur catta) in diverse habitats across southern Madagascar

We examined the mechanisms guiding male affiliative relationships among ring-tailed lemurs (Lemur catta) to investigate the adaptive significance of male social bonds in a female dominant, strictly seasonally breeding strepsirhine primate. To test whether male affiliative relationships were driven by reproductive and/or ecological conditions, we compared the frequency of male affiliation across the annual reproductive cycle in populations of L. catta inhabiting three habitat types found within its geographic range: (1) gallery forest at Beza Mahafaly Special Reserve in southwestern Madagascar; (2) spiny bush at Cap Sainte-Marie (CSM) in southern Madagascar; and (3) rocky-outcrop forest fragments at Anja Reserve and the Tsaranoro Valley in Madagascar’s south-central highlands. Each study period spanned the gestation, lactation/migration, post-migration, and mating periods. Inter-male affiliation rates varied across reproductive periods at each of the four sites, with the highest frequencies being observed during the gestation and lactation/migration periods and the lowest frequencies occurring during the mating period. In contrast, we found no clear patterns in male–female affiliation rates with respect to reproductive period. Comparing the Beza Mahafaly and CSM populations, rates of inter-male affiliation were higher at CSM during the gestation and lactation/migration periods, and rates male–female affiliation were higher at CSM across all seasons except the post-migration period. We suggest that inter-male affiliative relationships in L. catta may provide beneficial social interactions (i.e., grooming, ectoparasite control, predator protection, vigilance against extra-group male agonism) when females are unavailable, particularly during male dispersal, as well as under harsh climatic conditions characteristic of some L. catta habitats.

Bird fossils from Ankilitelo Cave: inference about Holocene environmental changes in southwestern Madagascar.

The identifications of non-permineralized fossil bird bones recovered from Ankilitelo Cave in southwestern Madagascar are presented. Among the more than 560 elements recovered, 29 different taxa were identified, the vast majority being species that still occur in this region of the island. Eggshell remains from the extinct elephant bird (Family Aepyornithidae) and assigned to Aepyornis sp. were found at the site. Two identified extant taxa, Scopus umbretta and Monias benschi, no longer occur in the area immediately surrounding the cave. The available radiocarbon measurements of collagen from fossil bird bones and avian eggshell carbonate of recovered from the cave range from 13,270 Cal yr BP to modern times. Hence, the presumed ecological shifts that took place resulting in the disappearance or range contractions of these three taxa is within the Holocene and are presumed to be associated with natural climatic change and in more recent centuries associated human pressures. Information is also presented on the origin of guinea fowl (Numida) and inference on the period of colonization of Corvus albus on Madagascar.

Limestone cliff - face and cave use by wild ring-tailed lemurs (<i>Lemur catta</i>) in southwestern Madagascar

Ring - tailed lemurs live in a range of habitats in southwestern Madagascar. To date, much of the knowledge of ring - tailed lemur ecology, biology and behavior come from riverine gallery forests sites. Recent years have seen an expansion of comprehensive research on this resilient species, including areas of limestone spiny forest along Madagascar’s southwestern coast. This work is documenting newly discovered behaviors by this species. The regular use of cliff - faces and embedded crevices and caves by ring - tailed lemurs in southwestern Madagascar are reported here. Cave use by several anthropoid primates has been explained as a thermoregulatory behavior. It is suggested that cliff - face and cave use by these ring-tailed lemurs serves several purposes, including resource acquisition, thermoregulation, and as an anti - predator avoidance strategy in the absence of suitable large sleeping trees. Observations indicate that the limestone boundaries of the Mahafaly Plateau and their associated xerophytic scrub forests warrant further conservation attention, given the presence of behavioral variation and increasing threats to this endangered primate species.

Epitypification and ecological notes for the Malagasy holoparasite Hydnora esculenta (Hydnoraceae)

The root holoparasite, Hydnora esculenta is a poorly known perennial herb described from southwestern Madagascar. The key character in the original diagnosis was floral dimorphism, a hermaphroditic form and an apparently thinner and longer sterile form. Other useful diagnostic characters are lacking. The type specimens consist only of slices of fruit, and lack important diagnostic characters, thus, an epitype is designated here. The original description is amplified based on field collections and examination of available herbarium material. Flowers of H. esculenta are variable in size (11.6–26.9 cm long) and merosity (3–6), but are uniformly hermaphroditic like all other Hydnoraceae. Osmophores situated on tepal apices combined with angular rhizomes separate H. esculenta from other known Hydnora spp. Additionally, ribbed tepal margins for H. esculenta are diagnostic and are preserved on herbarium specimens. Pollination biology follows the general pattern for the genus, brood‐site mimicry with insect imprisonment and release. Floral mobbing events by the putative pollinator, a scavenger scarab beetle (Kuijtenous laviceps) are reported. The most common observed host of H. esculenta was the invasive tree Pithocellobium dulce. The range of H. esculenta maybe increasing due to the spread of P. dulce in riparian areas and disturbed habitats in southern Madagascar.

Jatropha mahafalensis oil from Madagascar: Properties and suitability as liquid biofuel

Access to affordable and renewable sources of energy is crucial to reducing poverty and enhancing rural development in countries of the global South. Straight vegetable oil was recently identified as a possible alternative to conventional biomass for rural energy supply. In this context, the Jatropha curcas Linn. species has been extensively investigated with regard to its potential as a biofuel feedstock. In contrast, only little is known about Jatropha mahafalensis Jum. & H. Perrier, which is an indigenous and endemic representative of the Jatropha genus in Madagascar. This paper explores the potential and suitability of J. mahafalensis as a biofuel feedstock. Seed samples were collected in the area of Soalara in south-western Madagascar in February and September 2011. Two agro-ecological zones (coastal area and calcareous plateau) and two plant age groups (below and above 10years) were considered. These four sample groups were analyzed with regard to oil properties, element contents, and fatty acid profiles. Measured values differed greatly between the two harvests, probably owing to different climatic or storage conditions. No direct relation between age of trees or location and oil quality could be established. The analyses indicate that J. mahafalensis oil can be used in oil lamps, cooking stoves and stationary combustion engines for electrification or for biodiesel production. However, modifications in storage and extraction methods, as well as further processing steps are necessary to enable its utilization as a straight vegetable oil and feedstock for biodiesel production. If these technical requirements can be met, and if it turns out that J. mahafalensis oil is economically competitive in comparison with firewood, charcoal, paraffin and petroleum, it can be considered as a promising feedstock for rural energy supply.

Beyond Mean and Variance: Economic Risk Versus Perceived Risk of Farming, Foraging, and Fishing Activities in Southwestern Madagascar

Economic analyses of risk typically employ mean and variance calculations such as the coefficient of variation (CV) and z-score model. In this study we examine to what degree these simple measures approximate people’s perceptions of the risk associated with different farming, foraging, and fishing subsistence activities in southwestern Madagascar. CV calculated using production data for 15 activities (ranked) explains about 18 % of participants’ risk ratings from 24 focus groups. CV corresponds better to the ratings of men (37 %) and farmers (40 %), but does not predict the ratings by women, foragers, or Vezo fishermen, suggesting that economic measures of risk have a male and agrarian bias. Narrative responses suggest that risk is qualitatively different for foragers and fishermen, who face hazard (danger) and the cosmological dread of dying far from home. We conclude by predicting the ethnographic and ecological contexts when researchers should go beyond mean and variance when estimating risk.

Revision of the Endemic Malagasy Cavefish GenusTyphleotris(Teleostei: Gobiiformes: Milyeringidae), with Discussion of its Phylogenetic Placement and Description of a New Species

Troglobitic cavefishes of the genus Typhleotris, endemic to coastal southwestern Madagascar, are taxonomically reviewed and a new darkly pigmented species, Typhleotris mararybe, is described from an isolated karst sinkhole on the coastal plain below the Mahafaly Plateau. The new species, known only from Grotte de Vitane (Vitany) near the town of Itampolo, is unique among blind cavefishes in being uniformly darkly pigmented, rather than fully depigmented or exceptionally light in coloration. In addition to its dark coloration (vs. depigmented, translucent white body in congeners), the new species can be distinguished from its two congeners, Typhleotris madagascariensis and T. pauliani, by the sculpted, bony (vs. fleshy) appearance of its head with strongly protruding lateral ethmoid, sphenotic, and pterotic bones, and an elevated vertebral count.

Ontogeny in the Malagasy Traversodontid Dadadon isaloi and a Reconsideration of its Phylogenetic Relationships

Abstract New craniodental material of the traversodontid Dadadon isaloi from Middle/Upper Triassic basal “Isalo II” beds of southwestern Madagascar is described. These specimens reveal several new autapomorphies of Dadadon, including paired foramina on the frontal near the anterior border of the postorbital and lower incisors with denticulated distal margins. The new material covers a broad size range, providing the first information on ontogeny in Dadadon. Larger (presumably older) specimens of Dadadon isaloi have more postcanine teeth, relatively longer, narrower snouts, and a higher degree of cranial ornamentation than smaller specimens. Postcanine replacement in Dadadon was similar to that of other traversodontids: new teeth erupted at the posterior end of the postcanine tooth row and moved forward. Using information from the new specimens, the position of Dadadon was tested in a new phylogenetic analysis of traversodontids. In the new analysis, Dadadon is strongly supported as a member of a clade als...

The first record of a trans-oceanic sister-group relationship between obligate vertebrate troglobites.

We show using the most complete phylogeny of one of the most species-rich orders of vertebrates (Gobiiformes), and calibrations from the rich fossil record of teleost fishes, that the genus Typhleotris, endemic to subterranean karst habitats in southwestern Madagascar, is the sister group to Milyeringa, endemic to similar subterranean systems in northwestern Australia. Both groups are eyeless, and our phylogenetic and biogeographic results show that these obligate cave fishes now found on opposite ends of the Indian Ocean (separated by nearly 7,000 km) are each others closest relatives and owe their origins to the break up of the southern supercontinent, Gondwana, at the end of the Cretaceous period. Trans-oceanic sister-group relationships are otherwise unknown between blind, cave-adapted vertebrates and our results provide an extraordinary case of Gondwanan vicariance.

Notes on bat diversity at Berenty Private Reserve and Beza Mahafaly Special Reserve in southern Madagascar

Surveys of bat diversity are rare for the southern domain of Madagascar. Mistnetting for bats took place at Berenty Private Reserve in southeastern Madagascar during a six months study in 2009 and at Beza Mahafaly Special Reserve in southwestern Madagascar for one month in 2011. At Berenty, Hipposideros commersoni, Triaenops rufus, Myotis goudoti, and Miniopterus spp. were captured along trails and clearings inside forests. Two bats, T. rufus and Miniopterus sp., were captured near the Beza Mahafaly Special Reserve. These captures increase the known bat diversity reported for both sites, but more surveys at Berenty and Beza Mahafaly are recommended.

Extinction and ecological retreat in a community of primates

The lemurs of Madagascar represent a prodigious adaptive radiation. At least 17 species ranging from 11 to 160 kg have become extinct during the past 2000 years. The effect of this loss on contemporary lemurs is unknown. The concept of competitive release favours the expansion of living species into vacant niches. Alternatively, factors that triggered the extinction of some species could have also reduced community-wide niche breadth. Here, we use radiocarbon and stable isotope data to examine temporal shifts in the niches of extant lemur species following the extinction of eight large-bodied species. We focus on southwestern Madagascar and report profound isotopic shifts, both from the time when now-extinct lemurs abounded and from the time immediately following their decline to the present. Unexpectedly, the past environments exploited by lemurs were drier than the protected (albeit often degraded) riparian habitats assumed to be ideal for lemurs today. Neither competitive release nor niche contraction can explain these observed trends. We develop an alternative hypothesis: ecological retreat, which suggests that factors surrounding extinction may force surviving species into marginal or previously unfilled niches.

Dental topography indicates ecological contraction of lemur communities

Understanding the paleoecology of extinct subfossil lemurs requires reconstruction of dietary preferences. Tooth morphology is strongly correlated with diet in living primates and is appropriate for inferring dietary ecology. Recently, dental topographic analysis has shown great promise in reconstructing diet from molar tooth form. Compared with traditionally used shearing metrics, dental topography is better suited for the extraordinary diversity of tooth form among subfossil lemurs and has been shown to be less sensitive to phylogenetic sources of shape variation. Specifically, we computed orientation patch counts rotated (OPCR) and Dirichlet normal energy (DNE) of molar teeth belonging to 14 species of subfossil lemurs and compared these values to those of an extant lemur sample. The two metrics succeeded in separating species in a manner that provides insights into both food processing and diet. We used them to examine the changes in lemur community ecology in Southern and Southwestern Madagascar that accompanied the extinction of giant lemurs. We show that the poverty of Madagascar's frugivore community is a long-standing phenomenon and that extinction of large-bodied lemurs in the South and Southwest resulted not merely in a loss of guild elements but also, most likely, in changes in the ecology of extant lemurs.

Interpreting food processing through dietary mechanical properties: A Lemur catta case study

Knowledge of dietary mechanical properties can be informative about physical consequences to consumers during ingestion and mastication. In this article, we examine how Tamarindus indica fruits can affect dental morphology in a population of ring-tailed lemurs (Lemur catta) at Beza Mahafaly special reserve in southwestern Madagascar. Ring-tailed lemurs in tamarind dominated gallery forests exhibit extreme wear and tooth loss on their postcanine dentition that has been related to processing T. indica fruits. We measured and compared mechanical properties of individual food parts in the diet of ring-tailed lemurs in different seasons in 1999-2000, 2008, and 2010. Fracture toughness, hardness, and modulus of foods were measured with a portable mechanical tester. The ripe fruits of T. indica are indeed the toughest and hardest foods ingested by the lemurs. In addition, they are among the largest foods consumed, require high numbers of ingestive bites to process, and are the most frequently eaten by volume. During controlled cutting tests of the ripe fruit shell, multiple runaway side cracks form alongside the cut. Similarly, the lemurs repeatedly bite the ripe shell during feeding and thereby introduce multiple cracks that eventually fragment the shell. Studies of enamel microstructure (e.g., Lucas et al.: BioEssays 30 (2008) 374-385; Campbell et al., 2011) advance the idea that the thin enamel of ring-tailed lemur teeth is susceptible to substantial micro-cracking that rapidly erodes the teeth. We conclude that micro-cracking from repeated loads, in combination with the mechanical and physical properties of the fruit, is primarily responsible for the observed dental damage.

Do Risk and Time Experimental Choices Represent Individual Strategies for Coping with Poverty or Conformity to Social Norms?

This study revisits a debate played out in Current Anthropology as to whether subsistence decisions are the result of individual strategy to cope with poverty and increase wealth (advanced by Kuznar in 2001 and 2002) or conformity to social norms (advanced by Henrich and McElreath in 2002)—a debate that mirrors discussions within the behavioral sciences about individual versus social learning and within the social sciences about agency versus structure. This study, set in southwestern Madagascar, goes beyond previous investigations by examining the influence on choices in simple risk and time preference experiments of multiple measures of income, wealth, status, and need, as well as conformity at three nested levels: ethnicity (Masikoro, Mikea, and Vezo), village, and clan. Logistic regression models found that both wealth and income variables and social group memberships predict choices, where the best-fit model, evaluated with the Akaike Information Criterion, combined income and either ethnicity or vil...

Ecology and Population Dynamics of Solitary Red Locusts in Southern Madagascar

This paper summarizes eight years of field study on the Red Locust, Nomadacris septemfasciata (Serville) in southwestern Madagascar and presents management recommendations for its control. This crop pest exhibits a fairly uniform annual life-cycle phenology in southern Madagascar, which involves seasonal migration and adult reproductive diapause. There is one generation/y. Eggs are laid at the beginning of the rainy season in November and December. Eggs hatch in 24–36 d, and the hatchlings reach adulthood in 50–70 d. Fledgling adults enter a reproductive diapause in March and April, and then migrate north and northeast to higher elevations (refuge area where rainfall is > 80 cm/y) where they remain throughout the dry season (May–October). In November (the beginning of the rainy season), the adults migrate south and west to lower elevations (breeding area where rainfall averages 40–80 cm/y) where they mate and initiate oocyte development. Females possess ∼ 162 ovarioles, and typically lay two or three egg pods, each containing ∼ 100 eggs. The six-month adult reproductive diapause is controlled by photoperiod. Eggs and nymphs can experience high mortality, and hence, these stages are key to predicting population dynamics. Based on our findings, we recommend concentrating surveys in the main breeding areas (including one small southwestern fringe with the strongest probability of gregarisation and outbreak), better monitoring of local rainfall abundance and distribution, and better monitoring of deforestation, which increases locust habitat.

Evaluating ring‐tailed lemurs (Lemur catta) from southwestern Madagascar for a genetic population bottleneck

In light of historical and recent anthropogenic influences on Malagasy primate populations, in this study ring-tailed lemur (Lemur catta) samples from two sites in southwestern Madagascar, Beza Mahafaly Special Reserve (BMSR) and Tsimanampetsotsa National Park (TNP), were evaluated for the genetic signature of a population bottleneck. A total of 45 individuals (20 from BMSR and 25 from TNP) were genotyped at seven microsatellite loci. Three methods were used to evaluate these populations for evidence of a historical bottleneck: M-ratio, mode-shift, and heterozygosity excess tests. Three mutation models were used for heterozygosity excess tests: the stepwise mutation model (SMM), two-phase model (TPM), and infinite allele model (IAM). M-ratio estimations indicated a potential bottleneck in both populations under some conditions. Although mode-shift tests did not strongly indicate a population bottleneck in the recent historical past when samples from all individuals were included, a female-only analysis indicated a potential bottleneck in TNP. Heterozygosity excess was indicated under two of the three mutation models (IAM and TPM), with TNP showing stronger evidence of heterozygosity excess than BMSR. Taken together, these results suggest that a bottleneck may have occurred among L. catta in southwestern Madagascar in the recent past. Given knowledge of how current major stochastic climatic events and human-induced change can negatively impact extant lemur populations, it is reasonable that comparable events in the historical past could have caused a population bottleneck. This evaluation additionally functions to highlight the continuing environmental and anthropogenic challenges faced by lemurs in southwestern Madagascar.

New material of Dadadon isaloi (Cynodontia, Traversodontidae) from the Triassic of Madagascar

ABSTRACT New material of the traversodontid cynodont Dadadon isaloi from the Triassic of southwestern Madagascar is described. The new material consists of a complete, well-preserved skull (FMNH PR 2232) and an unassociated, partial lower jaw (UA 10608). The new material reveals several novel aspects of Dadadon's morphology. Newly recognized autapomorphies that diagnose Dadadon include a fourth upper incisor with posterior accessory cusp, deep interorbital depressions confined to the frontals, and a very tall, robust mid-frontal ridge. Dadadon can further be distinguished from the similar traversodontids Massetognathus and Santacruzodon by the presence of shorter, broader prefrontals with prominent dorsal depressions, robust anterolateral processes overhanging the orbits, a single cusp in the anterior cingulum of the upper postcanines, and relatively elongate, striated, conical upper incisors. In a revised phylogenetic analysis incorporating data from the new specimens, Dadadon is recovered in a clade with Massetognathus and Santacruzodon. This clade is the sister taxon to the well-supported traversodontid subclade Gomphodontosuchinae. The ‘basal Isalo II’ cynodont fauna from Madagascar is more similar in composition to that of South America than to mainland Africa, although this is probably attributable to the lack of Ladinian–Carnian therapsid fossils on the mainland rather than an actual biogeographic pattern.

Aggregated Drinking Behavior of Radiated Tortoises (Astrochelys radiata) in Arid Southwestern Madagascar

Abstract While conducting a monitoring program in arid southwestern Madagascar we observed a large aggregation of ca. 100 radiated tortoises (Astrochelys radiata) along ca. 80 m of dry creek bottom at the onset of the wet season. Tortoises had apparently anticipated rainfall and as precipitation ensued, immediately began drinking from small depressions in the bedrock. We discuss potential mechanisms and consequences of the behavior and compare it with similar observations in desert tortoises (Gopherus agassizii).

When the Wealthy Are Poor: Poverty Explanations and Local Perspectives in Southwestern Madagascar

ABSTRACT To reduce poverty, one must understand what poverty means in local contexts. We used focus groups to elicit a “folk model” of poverty from Masikoro, Vezo, and Mikea people in rural southwestern Madagascar and then placed this model in dialogue with four social science models: economic growth, substantivism, mode of production, and livelihoods. The folk model emphasizes household continuity, production of people, and exploitative expropriation by the wealthy. Absent from the folk model is scarcity of natural and social resources, the core of economic growth and livelihoods explanations. Consistent with substantivism, poverty and wealth are states one may occupy simultaneously, not maximizable quantities. Compatible with mode of production, the root cause of poverty is the rules regarding control over property. Poverty interventions based on profit, competition, intensification, or devolution of control to traditional social institutions would likely be culturally foreign to rural Malagasy and could further the gap between rich and poor.

Combined Analysis by GC(RI), GC-MS and 13C NMR of the Essential Oil from Tana bojeriana (Apiaceae), an Endemic Species of Madagascar

Integrated analysis by complementary analytical techniques [CC, GC in combination withRetention Indices, GC-MS and 13C NMR] of the volatile components isolated from the aerial parts of Tana bojeriana (Baker) B.-E.van Wyk (Apiaceae), growing wild in South-Western Madagascar, was carried out before flowering and during full flowering periods. The composition of the essential oil was dominated by monoterpenes: α-phellandrene (28.3 - 50.0 %), limonene (10.5 - 23.1 %), carvone (1.7 - 22.8 %) and dill ether (7.7 - 17.8 %). Identification of some minor components was achieved by GC(RI) and 13C NMR after fractionation of one oil sample.