Food mechanical properties in three sympatric species of Hapalemur in Ranomafana National Park,Madagascar

We investigated mechanical dietary properties of sympatric bamboo lemurs, Hapalemur g. griseus, H. aureus, and H. (Prolemur) simus, in Ranomafana National Park, Madagascar. Each lemur species relies on bamboo, though previous behavioral observations found that they specialize on different parts of a common resource (Tan: Int J Primatol 20 1999 547–566; Tan: PhD dissertation 2000 State University of New York, Stony Brook). On the basis of these earlier behavioral ecology studies, we hypothesized that specialization on bamboo is related to differences in mechanical properties of specific parts. We quantified mechanical properties of individual plant parts from the diets of the bamboo lemur species using a portable tester. The diets of the Hapalemur spp. exhibited high levels of mechanical heterogeneity. The lemurs, however, could be segregated based on the most challenging (i.e., mechanically demanding) foods. Giant bamboo culm pith was the toughest and stiffest food eaten, and its sole lemur consumer, H. simus, had the most challenging diet. However, the mechanical dietary properties of H. simus and H. aureus overlapped considerably. In the cases where lemur species converged on the same bamboo part, the size of the part eaten increased with body size. Plant parts that were harvested orally but not necessarily masticated were the most demanding, indicating that food preparation may place significant loads on the masticatory apparatus. Finally, we describe how mechanical properties can influence feeding behavior. The elaborate procurement processes of H. simus feeding on culm pith and H. griseus and H. aureus feeding on young leaf bases are related to the toughnesses of protective coverings and the lemurs' exploitation of mechanical vulnerabilities in these plants. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Consumption of cyanogenic bamboo by a newly discovered species of bamboo lemur

Three species of bamboo-eating lemurs were found to be sympatric in the southeastern rain forests of Madagascar. Sympatric species generally differ in habitat utilization or diet, but these three closely related bamboo lemurs lived in the same habitat and all ate bamboo. Behavioral observation revealed that they did select different parts of the bamboo, and chemical analyses confirmed that there was a difference in the secondary compound content present in those selections. The growing tips of Cephalostachyum ef uiguieri selected by the golden bamboo lemur (Hapalemuraureus) contained 15 mg of cyanide per 100 g fresh weight bamboo while the leaves of C. perrieri selected by the gentle bamboo lemur (H. griseus)and the mature culms of C. cf uiguieri selected by the greater bamboolemur (H. simus) did not contain cyanide. Since each individual golden bamboo lemur ate about 500 g of bamboo per day, they daily ingestedabout 12 times the lethal dose of cyanide. The mechanism by which this small primate avoids the acute and chronic symptoms of cyanide poisioning is unknown.     

Quantitative variability of cyanogenesis in Cathariostachys madagascariensis—the main food plant of bamboo lemurs in Southeastern Madagascar

Giant bamboo (Cathariostachys madagascariensis) is a major food plant for three sympatric species of bamboo‐eating lemurs (Hapalemur aureus, H. griseus, and Prolemur simus) in the rain forests of southeastern Madagascar. This plant species is strongly cyanogenic. However, quantitative data on cyanide concentration in C. madagascariensis are scarce. Previous studies reported 15 mg cyanide per 100 g fresh shoot material (corresponding to approx. 57 µmol cyanide per gram dry weight). However, we found mean concentrations (±SE) ranging from 139.3±19.32 in ground shoots to 217.7±16.80 µmol cyanide per gram dry weight in branch shoots. Thus, cyanogenesis of C. madagascariensis was up to four times higher than reported before. In contrast to the strongly cyanogenic shoots no cyanide could be detected in differently aged leaves of C. madagascariensis confirming earlier studies. Within individual shoots fine‐scaled analysis revealed a characteristic ontogenetic pattern of cyanide accumulation. Highest concentrations were found in youngest parts near the apical meristem, whereas concentrations decreased in older shoot parts. Beyond the general intra‐individual variability of cyanogenic features analyses indicated site‐specific variability of both, the ontogenetic pattern of cyanide concentration as well as the total amount of cyanide accumulated in shoots. Additionally, analyses of soluble proteins—one important nutritive measure affecting food plant quality—demonstrated a converse quantitative relation of protein concentrations in leaves to cyanide concentration in shoots at the site‐specific level. We, thus, suggest integrative analyses on quantitative variation of cyanogenesis together with nutritive plant parameters in future studies. This approach would allow obtaining more detailed insights into spatial variability of giant bamboo's overall browse quality and its impact on lemur herbivores. Am. J. Primatol. 71:305–315, 2009. © 2009 Wiley‐Liss, Inc.     

Cytogenetic study of the Endemic Malagasy lemur: Hapalemur,I. Geoffroy, 1851

The genus Hapalemur Gray, 1870 is comprised of two species: H. simus Gray, 1870 and H. griseus Link, 1795. Hapalemur griseus contains, according to Osman Hill (1953), two species: H. g. griseus (Link, 1795) and H. g. olivaceus (I. Geoffroy, 1851). Recent ecological investigation by Petter & Peyrieras (1970) has helped the discovery of a third subspecies of H. griseus in the region of Lake Alaotra. Whilst making the cytogenetic study of the genus Hapalemur, we have completed the chromosomal evolution's schema, originated by Chu & Swomley (1961).     

Coping with low-quality diets: a first account of the feeding ecology of the southern gentle lemur, <Emphasis Type="Italic">Hapalemur meridionalis</Emphasis>, in the Mandena littoral forest,southeast Madagascar

Malagasy primates of the genus Hapalemur are exceptional in their exhibition of specialisations allowing for a folivorous diet despite their small body size. Members of this group are well known for their preference for specific parts of woody bamboo, the primary food resource throughout much of their range. The southern gentle lemur (H. meridionalis), however, inhabits littoral forests that contain little or no woody bamboo. Similar to its closely related congener, the Alaotran gentle lemur (H. alaotrensis), the question is raised as to how these lemurs subsist in this ecological context. The aim of this study was to gain an initial understanding of the ecological niche of the southern gentle lemur in the threatened ecosystem of the littoral forest of southeastern Madagascar. Lemurs were habituated and observed over a 3-month period during the austral winter, allowing for collection of both continuous and instantaneous focal data on their feeding ecology. Preferred food species were identified and collected, and biochemical analyses determined macronutrient and secondary compound values for consumed food items. The diet of the southern gentle lemur was found to be of low nutritional quality, as evaluated through the low protein-to-fibre ratio, especially when compared with other folivores. This lemur is also unique in spending a majority of its time grazing on terrestrial grasses (family Poaceae) during the resource-poor winter months. Our data indicate that Hapalemur spp. possess a behavioural flexibility, and possibly, digestive abilities, higher than previously thought for an animal of its small body size.     

Linking Laboratory and Field Approaches in Studying the Evolutionary Physiology of Biting in Bamboo Lemurs

A realistic understanding of primate morphological adaptations requires a multidisciplinary approach including experimental studies of physiological performance and field studies documenting natural behaviors and reproductive success. For primate feeding, integrative efforts combining experimental and ecological approaches are rare. We discuss methods for collecting maximum bite forces in the field as part of an integrated ecomorphological research design. Specifically, we compare maximum biting ability in 3 sympatric bamboo lemurs (Hapalemur simus, H. aureus, and H. griseus) at Ranomafana National Park, Madagascar to determine if biting performance contributes to the observed partitioning of a shared bamboo diet. We assessed performance by recording maximum bite forces via jaw-muscle stimulations in anesthetized subjects from each species. Behavioral observations and food properties testing show that the largest species, Hapalemur simus, consumes the largest and most mechanically challenging foods. Our results suggest that Hapalemur simus can generate larger bite forces on average than those of the 2 smaller species. However, the overlap in maximum biting ability between Hapalemur simus and H. aureus indicates that biting performance cannot be the sole factor driving dietary segregation. Though maximum bite force does not fully explain dietary segregation, we hypothesize that size-related increases in both maximum bite force and jaw robusticity provide Hapalemur simus with an improved ability to process routinely its more obdurate diet. We demonstrate the feasibility of collecting physiological, ecological, and morphological data on the same free-ranging primates in their natural habitats. Integrating traditionally laboratory-based approaches with field studies broadens the range of potential primate species for physiological research and fosters improved tests of hypothesized feeding adaptations.     

Confirmation of the specific status ofHapalemur aureus (Primates,Strepsirhini) by restriction genomic DNA banding patterns

This study confirms, on the basis of our molecular biology results and in accordance with cytogenetic, morphological and ethological data, the specific status ofHapalemur aureus. Furthermore, it appears clearly thatHapalemr simus began its differentiation fromHapalemur griseus griseus andHapalemur aureus (wich have a common branch) shortly after the separation ofLemur catta from the phylogenetic tree of theL. catta/ Hapalemur group.     

Habitat Preferences of the Critically Endangered Greater Bamboo Lemur (Prolemur simus) and Densities of One of Its Primary Food Sources, Madagascar Giant Bamboo (Cathariostachys madagascariensis), in Sites with Different Degrees of Anthropogenic and Natural Disturbance

Understanding the habitat preferences of a species is critical to the management and conservation of its population. The Critically Endangered greater bamboo lemur, Prolemur simus, is patchily distributed across its geographic range, using a very limited fraction of its total area of occurrence. The ecological basis for this patchy distribution remains largely unexplained. We analyzed the local habitat factors affecting the habitat use of Prolemur simus and densities of one of its primary food sources Madagascar giant bamboo, Cathariostachys madagascariensis. We sampled vegetation and site characteristics along belt transects in mid-altitude rain forest areas of the Ankeniheny–Zahamena rain forest corridor in eastern Madagascar, with (N?=?10) and without (N?=?16) evidence of habitat use by Prolemur simus. In our study site the preferred habitat type of Prolemur simus appears to be primary forest stands with moderate to low levels of human disturbance, greater natural disturbance, high densities of large diameter bamboo, and high structural diversity in tree heights. Cathariostachys madagascariensis appears to exploit canopy gaps created by natural disturbances, and similarly often exploits areas of anthropogenic disturbance. We found the highest densities of bamboo to occur in areas of moderate anthropogenic disturbance, whereas larger diameter culms were associated with lower levels of disturbance and smaller culms with areas of high anthropogenic disturbance. Human use of the forest and protection of the habitat of Prolemur simus are not necessarily incompatible, but our data indicate that the severity and frequency of use should probably be relatively low. Our results suggest that in our study site management strategies that minimize human disturbances, promote structural diversity in tree heights, and maintain relatively high densities of large-culmed bamboo may benefit populations of Prolemur simus.     

Seasonal variation in activity and diet in a small-bodied folivorous primate,Hapalemur griseus,in southeastern Madagascar

How small-bodied (500–1,200 g) folivorous prosimian primates cope with large amounts of foliage in their diet seasonally has yet to be determined for many species such as Hapalemur griseus, which specializes on bamboo. To address this issue, we present results on seasonal variation in activity and diet from a wild group of H. griseus in southeastern Madagascar. Throughout the study (which was conducted from July–November 1994 and July 1995–February 1996), H. griseus primarily fed on new growth from three species of bamboo: two species of liana bamboo and Cephalostachyum perrieri. Bamboo species were used in different ways seasonally; liana bamboo was consumed more during the dry, cool season, and C. perrieri was eaten more often during the wet, warm season. H. griseus also spent more of their time feeding and traveling than nocturnal folivores of similar body size during the dry season. During the warm wet season, H. griseus decreased the amount of time spent feeding and traveling and rested more often. We hypothesize that seasonal changes in activity may be primarily related to the distribution and availability of food sources and/or reproductive cycles. Am. J. Primatol. 43:211–223, 1997. © 1997 Wiley-Liss, Inc.     

Ecological Correlates to Lemur Community Structure in Southeast Madagascar

The Fandriana-Marolambo forest corridor is one of the largest (ca. 250,000 ha) and least explored tracts of unprotected forest in southeast Madagascar. Although published range maps show continuous distributions for many lemurs throughout the region, there are few data on lemur community structure in the corridor. We aimed to determine lemur community structure, with its ecological correlates (altitude, agriculture, selective logging, and hunting), in the Fandriana-Marolambo forest corridor. We surveyed 7 sites and sighted 4 nocturnal taxa (Avahi laniger, Cheirogaleus major, Lepilemur mustelinus, and Microcebus rufus) and 6 diurnal taxa (Eulemur rubriventer, E. fulvus rufus, E. f. fulvus, Propithecus diadema edwardsi, Hapalemur griseus griseus, and Varecia variegata variegata). Composition of the lemur community was broadly similar to that of nearby protected areas (Ranomafana and Mantadia National Parks). However, we sighted no Hapalemur aureus, H. simus, or Indri indri, and observed Propithecus diadema edwardsi and Varecia variegata variegata at only 1 site each. We sighted an apparent hybrid form of Eulemur fulvus fulvus and E. f. rufus that may represent a new hybrid zone for lemurs. After testing for spatial autocorrelation, lemur diversity correlates negatively with altitude and agricultural intensity. Though the Government of Madagascar is assessing the corridor as a new national park, we suggest conservation plans for local lemurs are complicated by population isolation and lack of data on minimum viable size of the proposed protected area.     

High Energy or Protein Concentrations in Food as Possible Offsets for Cyanide Consumption by Specialized Bamboo Lemurs in Madagascar

Plants producing toxic plant secondary metabolites (PSMs) deter folivores from feeding on them. Animals that can cope with noxious PSMs have a niche with a competitive advantage over other species. However, the ability to cope with toxic PSMs incurs the costs of detoxification. To assess possible compensations for the ingestion of toxic PSMs, we compare the chemical quality of plants consumed by bamboo lemurs (genera Hapalemur and Prolemur; strepsirrhine primates of Madagascar) in areas with and without bamboo. Some bamboo lemurs consume bamboo containing concentrations of cyanogenic substances 10–50 times above the average lethal dosage for mammals, and we postulate that animals consuming cyanogenic substances need supplementary protein or readily available energy for detoxification. We compared the chemical composition of food consumed by three species of bamboo lemurs that feed mainly (>80% of their time) on bamboo in the evergreen rainforest of Ranomafana (Madagascar) with published data of the diets of bamboo lemurs at two sites without highly cyanogenic plants (reed beds of Lac Alaotra and the evergreen littoral forest of Mandena) and with food of sympatric folivorous lemur species that do not feed on bamboo. Lemurs feeding on bamboo consumed up to twice as much protein as bamboo lemurs in areas without bamboo and sympatric lemur species that feed on leaves of trees. Concentrations of nonstructural carbohydrates (a source of energy) showed the opposite trend. This result supports the hypothesis that feeding on cyanogenic plants is linked to high protein intake, either as a source of protein or for sulfur-containing amino acids that can be used for detoxification. Owing to the high protein concentrations in bamboo, however, we cannot distinguish between the hypothesis that lemurs that eat bamboo target additional food items with higher protein from the hypothesis that lemurs feeding on bamboo unavoidably obtain higher concentrations of protein than animals feeding on leaves of trees, without an added nutritional benefit.     

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.     

Characterization of 14 microsatellite marker loci in the grey bamboo lemur (Hapalemur griseus)

Fourteen nuclear microsatellite loci were isolated from a genomic DNA library derived from a free‐ranging bamboo lemur (Hapalemur griseus griseus) from Ranomafana National Park, Madagascar. Expected and observed heterozygosity levels were determined for populations of bamboo lemurs from Ranomafana National Park and a nonprotected area near Tsinjoarivo, Madagascar. Although genotype frequencies for all but one marker were within Hardy–Weinberg expectations for the Tsinjoarivo population, this was not the case for the Ranomafana samples. It is probable that the deviation of genotype frequencies from Hardy–Weinberg expectations in Ranomafana was precipitated by the presence of two taxa within the sample population.     

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.     

Maintenance of female dominance in blue‐eyed black lemurs (Eulemur macaco flavifrons) and gray bamboo lemurs (Hapalemur griseus griseus) under semi‐free‐ranging and captive conditions

Several species of Malagasy prosimians are characterized by female dominance, an unusual trait among mammals. We compare the extent to which female dominance is displayed and the mechanisms that are used to maintain dominance in the frugivorous blue‐eyed black lemurs (Eulemur macaco flavifrons) and the folivorous gray bamboo lemurs (Hapalemur griseus griseus) housed at the Duke Lemur Center. All dominant–submissive interactions were recorded during 448 hr of focal animal observations. Both species of lemurs exhibited clear patterns of female dominance. However, the two species used aggressive dominance (defined as aggression+submission) and social dominance (defined as submission in the absence of aggression) to different extents in maintaining hierarchies within each group. The adult female blue‐eyed black lemurs used aggressive dominance (e.g., chase, cuff, bite) in more of their dominance interactions (66%) than did the adult female gray bamboo lemurs (40%). In both species, rates of aggressive dominance interactions were higher during feeding versus nonfeeding periods and while in smaller outdoor runs versus larger natural habitat enclosures, but the differences were not significant. Overall blue‐eyed black lemurs exhibit a more aggressive form of female dominance compared to the gray bamboo lemur. Zoo Biol 26:345–361, 2007. © 2007 Wiley‐Liss, Inc.     

Phylogenetic relationships between Hapalemur species and subspecies based on mitochondrial DNA sequences

Background  

Phylogenetic relationships of the genus Hapalemur remains controversial, particularly within the Hapalemur griseus species group. In order to obtain more information on the taxonomic status within this genus, and particularly in the cytogenetic distinct subspecies group of Hapalemur griseus, 357 bp sequence of cytochrome b and 438 bp of 12S mitochondrial DNAs were analyzed on a sample of animals captured in areas extending from the north to the south-east of Madagascar. This sample covers all cytogenetically defined types recognized of the genus Hapalemur.     

A test for conspecific cueing in two sympatric species of pupfish (<Emphasis Type="Italic">Cyprinodon beltrani</Emphasis>, <Emphasis Type="Italic">C. simus</Emphasis>)

In many fishes, individuals prefer to associate with phenotypically similar or conspecific individuals (conspecific cueing). Such phenotypic segregation can be an important evolutionary driver, for example, in intralacustric sympatric speciation processes. I examined conspecific cueing in two species of sympatric pupfish from Laguna Chichancanab in southern Mexico: the little shoaling and highly territorial Cyprinodon beltrani and the highly shoaling but non-territorial C. simus. Females were tested for shoal species preferences in two testing scenarios: (1) a sequential choice test where shoals of four conspecific or four heterospecific (Cyprinodon sp. or Poecilia reticulata) females were presented in succession, and (2) a simultaneous choice test where female shoals of both Cyprindon species were presented concurrently. Overall, higher shoaling in C. simus was corroborated in this study. In the sequential test, no effect of the type of stimulus shoal (con- or heterospecific) on shoaling behavior was detected. In the simultaneous tests, C. beltrani, but not C. simus females showed a preference for the conspecific shoal. It seems possible that C. simus females did not evolve species recognition mechanisms because no other Cyprinodon species in the Laguna Chichancanab shows equally high shoaling, which automatically leads to the formation of single-species (i.e., C. simus-) shoals. C. simus males do not establish long-term territories, but rather spawn within shoals, whereas C. beltrani females approach males in their breeding territories to spawn. I discuss that this behavioral difference still provides a powerful reproductive isolation mechanism even in the absence of conspecific cueing in C. simus.     

Cyanide action in plants — from toxic to regulatory

Recent biochemical and genetic studies on hydrogen cyanide (HCN) metabolism and function in plants were reviewed. The potential sources of endogenous cyanide and the pathways of its detoxification are outlined and the possible signaling routes by which cyanide exerts its physiological effects are discussed. Cyanide is produced in plant tissues as the result of hydrolysis of cyanogenic compounds and is also released as a co-product of ethylene biosynthesis. Most cyanide produced in plants is detoxified primarily by the key enzyme β-cyanoalanine synthase. The remaining HCN at non-toxic concentration may play a role of signaling molecule involved in the control of some metabolic processes in plants. So, HCN may play a dual role in plants, depending on its concentration. It may be used in defense against herbivores at high toxic concentration and may have a regulatory function at lower concentration. Special attention is given to the action of HCN during biotic and abiotic stresses, nitrate assimilation and seed germination. Intracellular signaling responses to HCN involve enhancement of reactive oxygen species (ROS) generation and the expression of cyanide-insensitive alternative oxidase (AOX) and ACC synthase (ACS) genes. The biochemical and cellular mechanisms of these responses are, however, not completely understood.     

Direct and Indirect Impacts of Raptor Predation on Lemurs in Southeastern Madagascar

I calculated rates of predation by 2 species of diurnal raptors, Polyboroides radiatus and Accipiter henstii, on the lemur community of Ranomafana National Park, Madagascar from 2700 h of observation and 470 prey deliveries at 7 nests of each hawk species. The 2 hawks consumed 7 of 12 lemurs found in the park region, with a body mass of 63–3500 g and including diurnal and nocturnal species of all group sizes. Calculations of predation rates indicate that raptor predation is a significant cause of mortality for lemur populations relative to other causes. Minimum rates of predation by Polyboroides radiatus and Accipiter henstii on Microcebus rufus, Cheirogaleus major, Avahi laniger, Hapalemur griseus, Eulemur fulvus rufus, Eulemur rubriventer, and Varecia variegata resulted in the raptors removing of 1–21% of the population per yr, similar to other rates of predation on primates documented in the literature. Modeling of lemur populations under varying levels of raptor predation pressure that I calculated found that one may attribute 3–17% of adult, juvenile, and infant mortality for nocturnal lemurs and 2–66% of adult, juvenile, and infant mortality for diurnal lemurs to diurnal raptor predation. Raptor predation may significantly depress intrinsic growth rates and carrying capacity of Avahi laniger, Hapalemur griseus, Eulemur fulvus rufus, Eulemur rubriventer, and Varecia variegata owing to their low fecundities, long life spans, and long age to sexual maturation. Nocturnal lemurs may best avoid predation by diurnal raptors by exhibiting a solitary lifestyle and cryptic antipredator tactics, whereas, diurnal lemurs benefit less by increasing group size than by using specific antipredator tactics.     

Bacteria of the <Emphasis Type="Italic">Burkholderia cepacia</Emphasis> complex are cyanogenic under biofilm and colonial growth conditions

Background  

The Burkholderia cepacia complex (Bcc) is a collection of nine genotypically distinct but phenotypically similar species. They show wide ecological diversity and include species that are used for promoting plant growth and bio-control as well species that are opportunistic pathogens of vulnerable patients. Over recent years the Bcc have emerged as problematic pathogens of the CF lung. Pseudomonas aeruginosa is another important CF pathogen. It is able to synthesise hydrogen cyanide (HCN), a potent inhibitor of cellular respiration. We have recently shown that HCN production by P. aeruginosa may have a role in CF pathogenesis. This paper describes an investigation of the ability of bacteria of the Bcc to make HCN.