Jörg U. Ganzhorn

Biogeographic Evolution of Madagascar's Microendemic Biota

The endemic species richness on Madagascar, relative to landmass area, is unparalleled in the world. Many organisms on the island have restricted geographical ranges. A comprehensive hypothesis explaining the evolution of this microendemism has yet to be developed. Using an analysis of watersheds in the context of Quaternary climatic shifts, we provide a new mechanistic model to explain the process of explosive speciation on the island. River catchments with sources at relatively low elevations were zones of isolation and hence led to the speciation of locally endemic taxa, whereas those at higher elevations were zones of retreat and dispersion and hence contain proportionately lower levels of microendemism. These results provide a framework for biogeographic and phylogeographic studies, as well as a basis for prioritizing conservation actions of the remaining natural forest habitats on the island.

Primates in Peril: The world's 25 most endangered primates 2008-2010

Here we report on the ninth iteration of the biennial listing of a consensus of the 25 primate species considered to be among the most endangered worldwide and the most in need of conservation measures. The 2016–2018 list of the world’s 25 most endangered primates has five species from Africa, six from Madagascar, nine from Asia, and five from the Neotropics.

Lemur social systems and their ecological basis

Patterns of Range Use and Social Organization of Ayeayes (Daubentonia madagascariensis) on Nosy Mangabe E.J. Sterling. The Socioecology of Eulemur macaco I.C. Colquhoun. Home Range and Diet in Red Ruffed Lemurs (Varecia variegata rubra) on the Masoala Peninsula, Madagascar M.M. Rigamonti. Male Transfer in Captive Ruffed Lemurs, Varecia variegata variegata F.J. White, et al. A Review of Predation on Lemurs S.M. Goodman, et al. Adaptation and Phylogenetic Constraints in the Antipredator Behavior of Ringtailed and Ruffed Lemurs J.M. Macedonia. Territoriality in Lemur catta Groups During the Birth Season at Berenty, Madagascar A. Jollly, et al. A New Interpretation of the Social Organization and Mating System of the Ringtailed Lemur (Lemur catta) M.L. Sauther, R.W. Sussman. Feeding Behavior of Lemur catta Females in Relation to their Physiological State H.R. Rasamimanana, E. Rafidinarivo. 8 additional articles. Index.

Physiology: hibernation in a tropical primate.

The Madagascan fat-tailed dwarf lemur, Cheirogaleus medius, hibernates in tree holes for seven months of the year, even though winter temperatures rise to over 30 °C. Here we show that this tropical primate relies on a flexible thermal response that depends on the properties of its tree hole: if the hole is poorly insulated, body temperature fluctuates widely, passively following the ambient temperature; if well insulated, body temperature stays fairly constant and the animal undergoes regular spells of arousal. Our findings indicate that arousals are determined by maximum body temperatures and that hypometabolism in hibernating animals is not necessarily coupled to a low body temperature.

Leaf chemistry and the biomass of folivorous primates in tropical forests

SummaryRecent results have suggested that the biomass of folivorous arboreal primates per unit area in Africa and Asia is positively correlated with the average quality of leaves, expressed as the ratio of protein to fiber concentrations in a given forest. This hypothesis has been tested in different forests of Madagascar. Leaf selection of all folivorous femus species was studied in relation to leaf chemistry. Except for two populations ofLepilemur subspecies all other folivorous lemur species (including two other subspecies ofLepilemur) select leaves with high concentrations of easily extractable protein or low concentrations of fiber, or both. This confirms the prominent role of these two components in leaf selection by folivorous lemurs. The average quality of mature leaves in a given forest, expressed as the ratio of protein to fiber concentrations, is positively correlated with the biomass of folivorous lemurs. This confirms the hypothesis tested and suggests rather uniform selection processes for arboreal folivorous primates across the world.

New Directions in Lemur Studies

1. Ancient DNA in subfossil lemurs A.D. Yoder, et al. 2. Past and present distributions of lemurs in Madagascar L.R. Godfrey, et al. 3. Skeletal morphology and the phylogeny of the lemuridae G.F.N. Randria. 4. Support preference of two sympatric lemur species L. Razafimanantsoa. 5. Field metabolic rate and the cost of ranging of the Red-tailed Sportive Lemur (Lepilemur ruficaudatus) S. Drack, et al. 6. Metabolic strategy and social behaviour in lemuridae M.E. Pereira, et al. 7. Cathemeral activity of Red-fronted Brown Lemurs (Eulemur fulvus rufus) in the Kirindy Forest/CFPF G. Donati, et al. 8. Social organisation of the Fat-tailed Dwarf Lemur (Cheirogaleus medius) in Northwestern Madagascar A.E. Mueller. 9. Demography and floating males in a population of Cheirogaleus medius J. Fietz. 10. Influence of social organisation patterns on food intake of Lemur catta in the Berenty Reserve H. Rasaminanana. 11. The importance of the Black Lemur (Eulemur macao) for seed dispersal in Lokobe Forest, Nosy Be C.R. Birkinshaw. 12. Taste discrimination in lemurs and other primates, and the relationships to distribution of plant allelochemicals in different habitats of Madagascar B. Simmen, et al. 13. Folivory in a Small-bodied Lemur T. Mutschler. 14. Conservation of the Alaotran Gentle Lemur A.T.C. Feistner. 15. Teaching primatology at the University of Mahajanga (NW Madagascar) U. Thalman, A. Zaramody. 16. Lemurs as flagships for conservation in Madagascar J.C. Durbin. Index.

Lemur diversity in Madagascar

A basic understanding of the taxonomy, diversity, and distributions of primates is essential for their conservation. This review of the status of the taxonomy of lemurs is based on a 5-d workshop entitled “Primate Taxonomy for the New Millennium,” held at the Disney Institute, Orlando, Florida, in February 2000. The aim is not to present a taxonomic revision, but to review our current understanding of the diversity and current and past ranges of lemurs and indicate where there is controversy, discrepancy, or lack of knowledge. Our goal therefore is to provide a baseline for future taxonomic investigation, as well as a clearer focus for research and conservation priorities. We here focus on the lemurs of Madagascar and recognize 5 families, 15 genera, and 99 species and subspecies. We list 39 species of lemurs described since 2000: 2 dwarf lemurs, Cheirogaleus; 11 mouse lemurs, Microcebus; a giant mouse lemur, Mirza; a bamboo lemur, Hapalemur; 17 sportive lemurs, Lepilemur; and 7 woolly lemurs, Avahi. Taxonomic revisions have resulted in the resurrection of a further 9 taxa. However, the figures do not represent the total diversity of Malagasy lemurs because more new species are being identified via new field studies and accompanying genetic research, and should be described in the near future.

PARASITE BURDEN AND CONSTITUTION OF MAJOR HISTOCOMPATIBILITY COMPLEX IN THE MALAGASY MOUSE LEMUR, MICROCEBUS MURINUS

Abstract We investigated the importance of the major histocompatibility complex (MHC) constitution on the parasite burden of free‐ranging mouse lemurs (Microcebus murinus) in four littoral forest fragments in southeastern Madagascar. Fourteen different MHC class II DRB‐exon 2 alleles were found in 228 individuals with high levels of sequence divergence between alleles. More nonsynonymous than synonymous substitutions in the functional important antigen recognition and binding sites indicated selection processes maintaining MHC polymorphism. Animals from the four forest fragments differed in their infection status (being infected or not), in the number of different nematode morphotypes per individual (NNI) as well as in the fecal egg counts (FEC) values. Heterozygosity in general was uncorrelated with any of these measures of infection. However, a positive relationship was found between specific alleles and parasite load. Whereas the common allele Mimu‐DRB*1 was more frequently found in infected individuals and in individuals with high NNI and FEC values (high parasite load), the rare alleles Mimu‐DRB*6 and 10 were more prevalent in uninfected individuals and in individuals with low NNI and FEC values (low parasite load). These three alleles associated with parasite load had unique amino acid motifs in the antigen binding sites. This distinguished them from the remaining 11 Mimu‐DRB alleles. Our results support the hypothesis that MHC polymorphism in M. murinus is maintained through pathogen‐driven selection acting by frequency‐dependent selection. This is the first study of the association of MHC variation and parasite burden in a free‐ranging primate.

High rates of extra-pair young in the pair-living fat-tailed dwarf lemur, Cheirogaleus medius

Abstract Cheirogaleids are one of the most primitive extant primate taxa in the world. Their lifestyle and mating system, therefore, have been considered to be representative for social systems in primate ancestors. Accepted models of social evolution in primates state that pair-bonding has evolved secondarily from diurnal group-living taxa and should therefore be constrained primarily to diurnal species. In contrast to these assumptions, the nocturnal fat-tailed dwarf lemur (Cheirogaleus medius) lives in permanent pairs, with obligate paternal care probably representing the evolutionary basis of pair-living. In this sociobiological field study, we analyzed the reproduction strategy of C. medius in the tropical forest of western Madagascar. In the rainy seasons from 1995 to 1999, 173 individuals of C. medius were captured and individually marked and 131 were genetically characterized through seven microsatellite loci. Additionally, 36 of these individuals were radio-tracked and observed. For 53 genotyped individuals, including 16 offspring, information about pair-bonding and family structure was known from field observations. Genetic analyses revealed that yearlings and infants living with an adult pair were in all cases sibs of the social mother. However, C. medius does not restrain from extra-pair copulations (EPCs) and a high rate of extra-pair paternity (44%) was detected. Males sired offspring with their female partners as well as with extra-pair females within the same year, indicating that males may increase their reproductive success by EPCs without necessarily running the risk of cuckoldry. Females on the other hand do not seem to run the risk of reduced paternal care, either because males cannot detect relatedness of young, or because they might even increase their inclusive fitness by raising offspring of closely related males. Since females reproduce preferentially with territory holders and no paternity could be assigned to floating males, superior genetic quality of the males might be crucial for female choice.

Carabid beetle community composition, body size, and fluctuating asymmetry along an urban-rural gradient

Within the goal of defining indicators (species or combinations of life history traits) for habitat quality in an urban environment we investigated effects of urbanization on the community composition and morphological characteristics of carabid beetles. Between May and July 2000 nine woodlots were sampled along three axes representing urban - rural gradients from the centre of the city of Hamburg to its rural borders. Species richness decreased towards the city centre and with increasing isolation of the sites but was uncorrelated with the size of the site. Species assemblages were highly nested making successive loss of species predictable. Responsivness towards urbanization could not be linked to specific life history traits. Body length of one species (Carabus nemoralis) declined towards the city centre. Four species were found at all sites. These four species showed differences in fluctuating asymmetry (FA) at the different sites that could not be interpreted as an indication of responses to habitat suitability. FA of the remaining species (species negatively affected by urbanization) increased towards the city centre and with increasing isolation of a site. This matched the prediction that FA indicates habitat quality. Thus, urban effects lead to changes of communities through a predictable loss of species, to a reduction in body size in one species, and to increased FA in species which are susceptible to urbanization. The results indicate that the different sites were islands in an urban matrix rather than parts of a green network which would allow free exchange of plants and animals within the city of Hamburg. Wir untersuchten den Einfluss von Verstadterung auf Laufkafergemeinschaften in Hamburg, Deutschland. Zwischen Mai und Juli 2000 wurden neun Fangorte entlang stadtischer Gradienten beprobt. die von relativ landlichen Gebieten an den Stadtgrenzen, bis hin zu Flachen im Stadtzentrum reichten. Die Artenzahl korrelierte negativ mit dem Grad der Isolierung und der Entfernung des Gebietes von der Peripherie, aber nicht mit der Grose eines Gebietes. Die gefundenen Artengemeinschaften wiesen strenge Schachtelung auf. Der Verlust bestimmter Arten war daher vorhersagbar, konnte aber nicht auf bestimmte Charakteristika (“life history traits”) der Arten zuruckgefuhrt werden. Die Korperlange von Carabus nemoralis nahm entlang des Gradienten ab. Nur vier Arten kamen im gesamten Stadtgebiet vor. Fluktuierende Asymmetrien (FA) dieser Arten konnten nicht sinnvoll mit Habitatqualitaten oder Verstadterung in Beziehung gesetzt werden. Die anderen Arten, die nach den Ergebnissen der Analysen zu geschachtelten Strukturen durch “Verstadterung” negativ beeinflusst waren (d.h. nicht an allen Orten und vor allem nicht im Stadtzentrum gefunden worden waren) zeigten zunehmende FA zum Stadtzentrum. Verstadterung fuhrte demnach zu vorhersagbaren Verlust an Arten, zu Reduktion der Korperlange einer Art und zu erhohten Asymmetrien bei Arten, die durch Verstadterung negativ beeinflusst wurden. Nach diesen Befunden kann das Ziel der offiziellen Politik, in Hamburg negative Effekte der Stadtentwicklung auf die Biodiversitat durch einen Verbund von Grunflachen und geschutzten Gebieten zu reduzieren, mit den heute noch verfugbaren Flachen nicht erreicht werden.