Deadwood Structural Properties May Influence Aye-Aye (Daubentonia madagascariensis) Extractive Foraging Behavior
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The identification of critical, limited natural resources for different primate species is important for advancing our understanding of behavioral ecology and toward future conservation efforts. The aye-aye (Daubentonia madagascariensis) is an Endangered nocturnal lemur with adaptations for accessing structurally defended foods: continuously growing incisors; an elongated, flexible middle finger; and a specialized auditory system. In some seasons, ca. 90% of the aye-aye’s diet consists of two structurally defended resources: 1) the larvae of wood boring insects, extracted after the aye-aye gnaws through decomposing bark (deadwood), and 2) the seeds of Canarium trees. Aye-ayes have very large individual home ranges relative to most other lemurs, possibly owing to limited resource availability. Identification of limiting dietary factor(s) is critical for our understanding of aye-aye behavioral ecology and future conservation efforts. To investigate whether aye-ayes equally access all deadwood resources within their range, we surveyed two 100 × 100 m forest plots within the territories of two aye-ayes at Sangasanga, Kianjavato, Madagascar. Only 2 of 150 deadwood specimens within the plots (1.3%) appeared to have been accessed by the aye-ayes. To test whether any external or internal deadwood properties explain aye-aye foraging preferences we recorded species, height and diameter, and quantified the internal tree density using a 3D acoustic tomograph for each foraged and nonforaged deadwood resource within the plots, plus 13 specimens (5 foraged and 8 nonforaged) outside the plots. We did not detect any statistically significant preferences for species, diameter, or height. However, results from the acoustic analysis tentatively indicated that aye-ayes are more likely to forage in trees with greater internal (≥6 cm from the bark) densities. This interior region may function as a sounding board in the tap-foraging process to help aye-ayes accurately identify potential grub-containing cavities in the outer 1–4 cm of deadwood.
KeywordsFood resource limitation Home range Percussive foraging Structurally defended food resources
Resource availability can be a major predictor of home range size for primate species (Di Bitetti 2001). For example, among lemurs in Madagascar, Milne-Edwards’ sifakas (Propithecus edwardsi) have relatively larger home ranges in environmentally disturbed, patchy habitats than conspecifics in primary habitats (Gerber et al. 2012). Similarly, ring-tailed lemurs (Lemur catta) in Beza Mahafaly expand their home ranges during the dry season, likely to accommodate seasonal resource scarcity (Sussman 1991).
In addition to expanded home range sizes, low forest productivity and patchy resource distribution may lead to decreased population densities (Hanya and Chapman 2012). Therefore, instances of solitary foraging behavior over large home ranges may be a consequence of food limitation. For example, it is hypothesized that the large, solitary home ranges of Bornean orangutans (Pongo pygmaeus) are an adaptive response to satisfying large nutrient requirements in the face of scarce food resources (Galdikas 1988; Mackinnon 1974; Singleton and van Schaik 2001).
We here investigated potential food resource limitations in the wild habitat of a solitary foraging primate with extensive home range sizes, the aye-aye (Daubentonia madagascariensis). The aye-aye is an Endangered nocturnal lemur endemic to Madagascar with an adult body mass of ca. 2.5 kg and the largest relative brain size of any extant strepsirrhine primate (Kaufman et al. 2005; Schwitzer et al. 2013; Smith and Jungers 1997; Sterling 1993). Aye-ayes are able to access structurally defended foods with the aid of number of morphological adaptations, including continuously growing incisors; an elongated, thin, and highly flexible middle finger; and a specialized auditory system (Cartmill 1974; Simons 1995; Sterling 1993).
The longest aye-aye behavioral study to date was conducted from 1989 to 1991 on Nosy Mangabe, an island to which nine aye-ayes were introduced in the 1960s (Sterling 1993, 1994). At this site, up to ca. 90% of the aye-aye's diet during hot-dry seasons consisted of two structurally defended resources: the larvae of wood-boring insects (extracted from decomposing bark and wood, i.e., deadwood) and the seeds of Canarium trees (Sterling 1993, 1994). On Nosy Mangabe and at other sites, smaller components of the aye-aye diet include tree sap, nectar, fruits, and adult insects (Iwano and Iwakawa 1988; Pollock et al. 1985; Sterling 1993, 1994).
Aye-ayes extract insect larvae from a variety of locations, including trunks and branches of dead trees, fallen deadwood, dead branches on living trees, bamboo, and —very rarely— living trees (Sefczek et al. 2012; Sterling 1994). The middle phalanx is used to tap on the bark of decaying trees to facilitate the detection of tree cavities that may contain grubs, in a process referred to as percussive foraging (Erickson 1994). Aye-ayes rely on the auditory interpretation of signals that are produced by rapidly tapping the outer surface of the tree to identify larval mines beneath the bark (Coleman and Ross 2004; Erickson 1994; Kaufman et al. 2005; Ramsier and Dominy 2012). The continuously growing incisors are then used to gouge holes in the trees, from which the insect larvae are skewered with the flexible middle digit (Erickson 1994; Sterling 1994).
Although insect larvae are often envisioned as the most important aye-aye food, researchers have alternatively suggested the nutrient-rich seeds of Canarium as a primary dietary resource (Iwano and Iwakawa 1988; Sterling 1993). Important Canarium species for aye-ayes include C. boivinii and C. madagascariensis (Iwano and Iwakawa 1988; Pollock et al. 1985; Simons 1995; Sterling 1993, 1994). To access the nut-like seeds of Canarium, aye-ayes use their superior incisors to chew through the mid-endocarp and their inferior incisors to pierce the endocarp before scraping out the interior with their middle finger (Sterling 1994).
The aye-aye has the largest geographical species distribution of any extant lemur, with populations observed in both the tropical rainforests along the east coast and the relatively dry forests of the west coast and northernmost regions of Madagascar (Sterling 2003). Aye-ayes also have among the largest individual home range (the core area of land within which an animal forages) sizes of any lemur: 120–215 ha for males and 30–40 ha for females on Nosy Mangabe (Sterling 1993). These home range sizes are extensive given that aye-ayes are solitary foragers with a ca. 2.5-kg body size (Smith and Jungers 1997; Sterling 1993). Although aye-ayes have smaller body sizes than orangutans, like orangutans they have relatively large, minimally overlapping (at least for aye-aye females) home ranges and solitary foraging behaviors that could reflect dependence on one or more limited food resources.
Studying potential food resource limitation is important for our understanding of aye-aye behavioral ecology and for future conservation efforts. With deforestation and the further loss of deadwood resources or live Canarium trees (the densities of which may vary across habitats), aye-ayes may be forced to range farther to satisfy dietary needs to avoid local extirpation (Farris et al. 2011; Sefczek et al.2012). In this study, we performed an initial investigation into potentially limiting factors of the aye-aye diet, focusing especially on deadwood. Specifically, to test whether deadwood in general is a limited resource we first assessed whether aye-ayes exploited all or a smaller portion of the available deadwood within their home ranges in order. Second, we investigated whether particular external or internal properties of deadwood or the proximity to living Canarium trees may affect aye-aye resource selection.
The Madagascar Biodiversity Partnership at the Kianjavato Ahmanson Field Station actively monitors and collects behavioral data on GPS- and radio-collared aye-ayes at Sangasanga. Our specific study plots (Fig. 1b) were located within the active home ranges of two collared adult aye-aye individuals (one adult male and one adult female; the female had a single offspring during the time of the study), in a zone of humid secondary lowland rainforest ca. 0.69 km from the village, the periphery of which is adjacent to the forest boundary. The collared aye-ayes range across all of the aforementioned forest regions (Manjaribe et al. 2013; Solofondranohatra 2014). The well-documented ranging patterns and foraging habits of aye-ayes within this area, along with Sangasanga’s topographic, botanical, and level of anthropogenic disturbance variation made it an ideal site for this study.
Inventory of Tree Distribution
Our goal was to perform an initial test of potentially limiting food resources in the aye-aye home range, including of deadwood in general, particular external or internal properties of deadwood, and the proximity of deadwood to live Canarium trees. Densities of Canarium are largely unquantified in southeastern Madagascar rainforests, with the limited available data suggesting a patchy pattern of distribution (Farris et al. 2011; Sefczek et al. 2012). Therefore, we chose to survey two relatively large plots (100 × 100 m each) rather than a greater number of smaller plots or transects, hoping that the plots would each encompass multiple specimens of Canarium.
We established one 100 × 100 m plot in the low-elevation, disturbed forest zone and a second 100 × 100 m plot in the medium to high-elevation, dense forest zone. We placed plots within areas of frequent use in the home ranges of the two radio-collared individuals, and far from any of the ranges’ boundaries. We recorded the diameter (specifically diameter at breast height [DBH]), height, vernacular name, and GPS location (using a Garmin GPSmap 62) of each deadwood resource and living Canarium tree specimen. We measured DBH using two observers of identical stature (160 cm with DBH measured at ca. 119 cm). At breast height, the researchers took measurements using a DBH forestry measuring tape (which displays both the circumference and diameter). In the event that deadwood resources were <119 cm in height, diameter was taken at the highest available point.
We measured tree heights directly using a meter tape where the full length of the specimen was accessible or could be safely climbed, and visually estimated when part of the specimen was inaccessible or beyond the reach of equipment. We identified all deadwood and Canarium specimens according to Malagasy vernacular names by bark and appearance. We later translated vernacular names to scientific names whenever possible. We included in this analysis only the deadwood specimens whose Malagasy vernacular names could be translated into scientific names. Of the translatable specimens, 23 could be identified only to the genus level; we therefore performed the analysis at this taxonomic level.
We identified all traces of aye-aye foraging for larvae, typically in deadwood. We also searched for traces on live trees, which are very occasional targets of aye-aye foraging (Sefczek et al.2012). Signs of foraging events included incisor indentations with funnel-shaped holes at the center of gnawed areas and bark shavings peeled away from the point of insertion; these traces served as proxies for direct foraging observations at a given tree (Duckworth 1993; Erickson 1994; Sefczek et al. 2012; Sterling 1993). We surveyed each deadwood resource extensively and on all sides, in daylight, by multiple members of the research team, including with binoculars. We are confident that we were able to identify the vast majority of aye-aye traces within the plots. Still, it is possible that we missed very small traces that were located higher in the canopy. Any such sampling error is expected to be small and is not anticipated to affect the overall conclusions of the study. Within the two 100 × 100 m plots, we identified a total of two foraged and 148 nonforaged deadwood resources. To increase our sample size of foraged deadwood for our external and internal tree property analyses, we additionally identified and examined a further five deadwood resources with aye-aye foraging traces and eight nonforaged deadwood resources that were outside the two fully surveyed 100 × 100 m plots but that were still located within the known ranges of the collared aye-aye individuals. These additional traces represented the most proximate instances of foraging beyond the boundaries of the plot but well within the aye-aye’s home range, plus nearby nonforaged specimens. The expanded sample size thus consisted of a total of 163 deadwood tree resources (foraged N = 7 and nonforaged N = 156).
Deadwood Internal Structural Property Measurement
Given the mechanics of the percussive “tap” foraging method of aye-aye larval extraction, variation in deadwood structural qualities may influence foraging ability or success. To estimate the internal density of foraged vs. nonforaged deadwood resources, we used a Fakopp Arborsonic 3D Acoustic Tomograph that estimates the velocity at which sound is conducted through the tree. This forestry machine distributes and receives sound waves across 10 sensors placed evenly around the circumference of a tree. Each sensor has thin, elongated prongs with precise sound sensors at the tip; these prongs are hammered into the bark of the tree. Each sensor is then tapped a minimum of three times, which propagates sound across the tree. The sensors are connected to a laptop, where the Fakopp Arborsonic software (with custom modifications for our study, Version 3) records the length of time taken for the sound to be received by each sensor. Sound travels at different speeds depending on the density of the substrate. It traverses more quickly through tightly packed (dense) molecules and more slowly across loosely packed molecules. The Arborsonic program renders two- and three-dimensional computer models of internal tree density based on the velocity of the sound traveling between the sensors. Therefore, scanning the deadwood specimens allowed us to quantify internal structural property variation that may influence aye-aye tap-foraging behavior.
For each deadwood tree resource, we performed five scans between 80- and 120-cm tree heights at ca. 5-cm intervals for nonforaged and ca. 2-cm intervals for foraged specimens. For shorter specimens, deeply decayed spots, or other tree malformations, we scanned as close as possible to the breast height of the tree. For foraged specimens, we took the five scans around the sites of aye-aye traces. The external bark of 2 of the 7 foraged and 109 of the 156 nonforaged deadwood tree resources were too decayed to hold the Acoustic Tomograph prongs tightly, precluding the ability to obtain accurate sound velocity data. For a minority (N = 7) of the nonforaged specimens included in the sample, it was not possible to collect a full five scans (Electronic Supplementary Material [ESM] Table SI). Our final sample sizes for the internal structural property analysis were thus 25 scans from 5 foraged trees and 224 scans from 47 nonforaged trees.
Means and test parameters for foraged vs. nonforaged deadwood comparisons
Nonforaged mean (±SE) [±SD]
Foraged mean (±SE) [±SD]
95% CI of the differencea
N values tested
N values tested
5.5 (±0.6) [±7.3]
6.9 (±2.2) [±5.8]
Diameter (of all specimens)
23 (±1.3) [±15.5]
18.9 (±4.1) [±10.7]
Diameter measured specifically at breast height (ca. 119 cm)
26.7 (±1.9) [±17.6]
18.9 (±4.1) [±4.1]
at 1 cm (all scan values)
1544.4 (±28.1) [±614.3]
1217.4 (±58.5) [±522.6]
at 2 cm (all scan values)
1598.8 (±28.6) [±625.5]
1366.3 (±74.5) [±665.9]
at 3 cm (all scan values)
1491.9 (±23.2) [±600.3]
1326.1 (±56.8) [±567.2]
at 4 cm (all scan values)
1372 (±21.4) [±607.9]
1370.4 (±74.3) [±574.8]
at 5 cm (all scan values)
1298 (±22.3) [±623.6]
1414.4 (±70.5) [±545.8]
at 6 cm (all scan values)
1223.4 (±22.4) [±618.5]
1433.3 (±66.9) [±518.2]
at 7 cm (all scan values)
1116 (±19.7) [±522.5]
1433.3 (±64.7) [±500.5]
at 8 cm (all scan values)
1026.1 (±18.9) [±470]
1440.6 (±98.2) [±589.3]
at 1 cm (measured at 80–120 cm)
1547.9 (±65.5) [±692.7]
1498.3 (±85.6) [±567.4]
at 2 cm (measured at 80–120 cm)
1594 (±67.7) [±715.9]
1817.6 (±105.7) [±700.8]
at 3 cm (measured at 80–120 cm)
1500.9 (±56.6) [±678.8]
1598.2 (±76.7) [±612.9]
at 4 cm (measured at 80–120 cm)
1355.5 (±49.3) [±675.3]
1530.1 (±94.4) [±597]
at 5 cm (measured at 80–120 cm)
1213.6 (±51) [±699]
1567.3 (±89.2) [±563.9]
at 6 cm (measured at 80–120 cm)
1128.9 (±48.5) [±692.3]
1575.7 (±84.6) [±535]
at 7 cm (measured at 80–120 cm)
942.6 (±34.2) [±463]
1567.5 (±81.8) [±517.3]
at 8 cm (measured at 80–120 cm)
835.5 (±25.8) [±333.7]
1581.6 (±161.3) [±721]
at 1 cm (one average value per deadwood specimen)
1515.7 (±92.3) [±479.3]
1217.4 (±174.5) [±349]
at 2 cm (one average value per deadwood specimen)
1565.4 (±100.3) [±521.2]
1366.3 (±239.5) [±478.9]
at 3 cm (one average value per deadwood specimen)
1426 (±82.7) [±529.5]
1326.1 (±167.1) [±373.6]
at 4 cm (one average value per deadwood specimen)
1358.3 (±82.7) [±548.1]
1370.4 (±189.2) [±327.7]
at 5 cm (one average value per deadwood specimen)
1293.4 (±87.4) [±573]
1414.4 (±164.3) [±284.5]
at 6 cm (one average value per deadwood specimen)
1241.4 (±91.4) [±584.7]
1433.3 (±146.2) [±253.2]
at 7 cm (one average value per deadwood specimen)
1141.8 (±81.5) [±505.7]
1433.3 (±135.5) [±234.7]
at 1 cm (measured at 80–120 cm, one average value per deadwood specimen)
1471.1 (±165) [±547.1]
1506.8 (±93.6) [±132.3]
at 2 cm (measured at 80–120 cm, one average value per deadwood specimen)
1517.9 (±186.2) [±617.5]
1808.4 (±101.2) [±143.2]
at 3 cm (measured at 80–120 cm, one average value per deadwood specimen)
1426.8 (±159.2) [±595.7]
1582.9 (±194.2) [±336.3]
at 4 cm (measured at 80–120 cm, one average value per deadwood specimen)
1334.3 (±152.1) [±608.3]
1530.1 (±175.8) [±248.6]
at 5 cm (measured at 80–120 cm, one average value per deadwood specimen)
1207 (±177.4) [±663.6]
1567.3 (±103.8) [±146.8]
at 6 cm (measured at 80–120 cm, one average value per deadwood specimen)
1140.2 (±182.4) [±657.5]
1575.7 (±56.7) [±80.1]
at 7 cm (measured at 80–120 cm, one average value per deadwood specimen)
999.8 (±137.8) [±477.1]
1567.5 (±31.8) [±45]
Deadwood Genus and External Properties
Within the two 100 × 100 m forest plots, only 2 of 150 total observed deadwood tree specimens (1.3%) had been accessed by the aye-ayes for insect larvae on the basis of visible signs of past extractive foraging (Fig. 1b). This result suggests that deadwood alone, i.e., without the consideration of any other variables, is not likely a limited resource for aye-ayes.
Deadwood Internal Structural Properties
The aforementioned results suggest that a different major aye-aye food resource, such as Canarium, may be the critical limiting resource in the aye-aye diet, or that the internal structural rather than external properties of deadwood might impact net nutritional gain from extractive foraging, or both. Unfortunately, as there were only two total foraged trees within our two 100 × 100 m plots and only five Canarium specimens (ESM Fig. S1), we were unable to statistically evaluate the Canarium proximity hypothesis in the present study. However, we were able to study variation in the internal properties of the deadwood resources by using the Fakopp Arborsonic 3D Acoustic Tomograph to estimate the velocity of sound traveling through the trees, a proxy for true density.
We observed that for the first 1–3 cm from the outer tree surfaces, the estimated velocity values were slightly but statistically significantly lower for foraged deadwood resources compared to nonforaged specimens (Fig. 4b). However, from 6 cm inward toward the center of the tree this pattern is reversed, with statistically significantly higher velocities for the foraged deadwood specimens. For example, at 6 cm, 7 cm, and 8 cm from the outer surface of the tree the average velocity estimates for foraged trees were 17%, 28%, and 40% greater, respectively, than those for nonforaged specimens (Welch two-sample t-tests: df = 73, P < 0.01; df = 71, P < 0.0001, and df = 38, P < 0.001; Fig. 4b).
Because we scanned foraged trees at the locations where traces occurred rather than strictly at DBH, the scanned heights were different for some of the foraged vs. nonforaged trees. However, when we restricted our comparison of foraged vs. nonforaged trees to only those scans that were taken from 80–120 cm heights (N = 3 foraged trees; N = 17 nonforaged trees), we observed similar results (ESM Fig. S2; t-tests for 6 cm, 7 cm, and 8 cm from tree outer surface: df = 68, P < 0.0001; df = 54, P < 0.0001; df = 20, P < 0.0001 respectively). Thus, while nonforaged trees have similar or slightly higher velocities on the 1- to 3-cm intervals compared to foraged trees, the deadwood resources selected by aye-ayes for insect larvae foraging tend to have relatively more intact interior cores compared to the overall sample of available deadwood.
The aforementioned t-tests of similarity for foraged vs. nonforaged velocity estimates likely violate the test’s assumption of independence among values. The density values from a given region of one deadwood specimen are likely related to the density values of different region within that same tree. Using a reduced dataset with a single mean velocity value for each cm interval per tree (see Methods) to repeat the analysis, only comparisons from the subset of 80–120 cm height scans remained statistically significant (all scans at 6 cm t-test: df = 4, P = 0.34; all scans at 7 cm t-test: df = 4, P = 0.15; subset of 80–120 cm scans at 6 cm t-test: df = 13, P = 0.05; subset of 80–120 cm scans at 7 cm t-test: df = 12, P < 0.01). Thus, our results should be considered tentative and preliminary until they can be replicated with a larger sample of foraged trees and, ideally, across additional aye-aye sites.
We here investigated the distribution and properties of deadwood, a potentially important resource for the aye-aye diet that —if limited in some manner— could explain why aye-ayes maintain such large individual home ranges. However, we found that only a small fraction of all deadwood resources within aye-aye home ranges are accessed for insect larvae. Thus, either deadwood itself is not a limiting resource for aye-ayes, or particular properties of the deadwood are important, such that only subsets of all deadwood resources are limiting dietary factors for aye-ayes. If deadwood alone was a limiting resource, then a higher rate of deadwood foraging would likely have been observed, as aye-ayes would be expected to attempt to maximize nutrient gain relative to travel distance by foraging at all available dead trees. Alternatively, aye-ayes might attempt to maximize nutrient gain by repeatedly foraging on a singular resource with high larval content, once such a resource is discovered. Although we did observe indirect evidence of this behavior, with one heavily foraged specimen, this was a novel occurrence and does not change our overall conclusions.
We next compared external variables of foraged vs. nonforaged deadwood resources, beginning with taxonomy. We did not observe a preference toward any given deadwood genus. In her previous work at Nosy Mangabe, Sterling observed aye-ayes foraging on at least 6 families of insect larvae inhabiting a minimum of 29 different tree genera (Sterling 1993, 1994). Our observation that aye-ayes do not exhibit a strong preference for specific deadwood taxa is consistent with Sterling’s original result. Besides taxonomy, we also considered tree height and diameter as potential limiting factors. Within our sample, height and diameter were not statistically significantly different between foraged and nonforaged deadwood trees. However, it appears that there could be some preference for foraging on trees with smaller diameters, which in turn could be related to the ability to grip the tree properly during percussive and extractive foraging. Still, aye-ayes foraged on only a fraction of all available shorter and smaller diameter deadwood resources, suggesting that deadwood tree height and diameter alone are not major limiting factors for the aye-aye diet.
Finally, we compared the internal structures of foraged vs. nonforaged deadwood resources. We found that beyond 5 cm inward from the outer tree surface, foraged trees propagate sound more efficiently, i.e., have higher densities. Although this result is based on a limited number of observations and should thus be considered preliminary, it at least sparks an intriguing hypothesis related to aye-aye deadwood foraging ecology. Specifically, a previous study of aye-aye percussive foraging behavior reported that most larval excavation events occur within the first 1–3 cm from the outer surface of trees (Erickson 1994). Following our results, we tentatively hypothesize that the area behind the larval mines toward the tree center may have an important function in the aye-aye percussive foraging process. Specifically, this region could serve as a reflective “sounding board,” with denser wood in this region facilitating more precise acoustic reconstruction of the tree’s outer 1–3 cm, leading to more efficient foraging for insect larvae. Another factor that may contribute to deadwood resource selection could be independent of the tree structural properties required for aye-aye percussive foraging perceptual capability; namely, whether larval location varies by resource density. It may be that larvae preferentially occupy certain trees or particular regions therein based on deadwood interior or exterior structural properties. This will be an interesting topic for future research.
As only 10% or less of Madagascar remains forested, species with large home ranges are increasingly vulnerable to extinction (Mittermeier et al. 2010). Given their large and minimally overlapping (for females) home ranges, it is likely that aye-aye population densities are naturally very low (Mittermeier et al. 2010; Sterling 1993). Such factors, in conjunction with the aye-aye’s slow life history and relatively low genetic diversity, may make aye-ayes especially vulnerable to extinction (Catlett et al. 2010; Perry et al. 2012a, b, 2013; Schwitzer et al. 2013). An understanding of the role that limited food resources play in determining home range size may be crucial to our efforts of preserving this unique and Endangered primate (Schwitzer et al. 2013). Home range sizes and minimum conservation areas needed to maintain healthy populations of aye-ayes may vary as functions of the densities of deadwood, bamboo, Canarium, or other food items that comprise a smaller proportion of the aye-aye diet but may be seasonally or nutritionally critical, if those critical food resources are variable among different forest types within the species range, e.g., wet tropical rainforest vs. dry deciduous forest. Therefore, in addition to larger sample sizes of foraged trees, expanded analyses of Canarium resource locations, and the inclusion of other dietary resources and potential larval foraging from bamboo, future studies should include deadwood specimens measured at different times of the year, as rainfall, humidity, and temperature may all alter the decay process. Future studies could also investigate the relationship between deadwood density and the abundance of wood-boring insect larvae. As insect and tree species may also vary from region to region, this study should also be conducted in several different known aye-aye habitats to provide a more comprehensive view of the foraging preferences of this Endangered species.
We thank the Government of Madagascar for the permission to conduct research and the Madagascar Biodiversity Project (MBP) and its staff at the Kianjavato Ahmanson Field Station for facilitating this study, especially Razafindrahasy Alexander Théofrico (Frico), Kotozafy Gilbert André (Abanky), Randriambololona Stéphan Justin (Tofa), Fanoharanomenjanahary Hubert El-Phanger (Dadah), and Razafindrazefa Elysé Fortinand (Dagah). We also thank John Wickes, Peter Divos, and Akos Smuck of Fakopp Enterprise for their help and expertise regarding the ArborSonic 3D Acoustic Tomograph machinery and analysis program; James S. Solofondranohatra of the University of Antananarivo for his insight into aye-aye behavior and assistance in the field; and Zach Farris and Tim Sefzeck for contributing their compiled databases on the vernacular to scientific name translations for Malagasy tree species. We thank Steig Johnson and Nate Dominy for comments and discussion that helped shape this study; Logan Kistler, Martin Welker, Jeoren Smaers, Andrew Zamora, Rosemary Miller, and Annie Lin for insights or assistance with data analysis; Tim Ryan, Logan Kistler, Becki Coleman, and Stephen Johnson for comments on an earlier draft of this manuscript; and the constructive comments from two anonymous reviewers, the associate editor, and the editor of the journal that helped us to improve the paper. Funding was provided by the American Society of Primatologists, the Pennsylvania State University College of the Liberal Arts, The Pennsylvania State University Huck Institutes of the Life Sciences, and the benefactors of Pennsylvania State University Schreyer Honors College.
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