Hematologic Values of Free-ranging Cebus cay and Cebus nigritus in Southern Brazil

We evaluated blood samples obtained from 80 free-ranging healthy capuchins (Cebus cay and C. nigritus) to establish hematological reference values and to assess the influence of sex and age on them. We caught the monkeys in the Paraná River region of Southern Brazil via manual or automatic traps. We anesthetized them intramuscularly with 3.6 mg/kg tiletamine/zolazepam hydrochlorides. After physical examinations, we divided the sample according to sex and age: 26 females (13 adults and 13 juveniles) and 54 males (27 adults and 27 juveniles). We collected blood and determined hematological values via traditional published methods. We analyzed data via 2-way ANOVA to test the effect of sex, age, and interactions between the 2 factors. The packed-cell volume was higher in adult males and the numbers of white blood cells and lymphocytes were higher in juveniles. There is no other significant difference.     

Anting in a Semifree-ranging Group of <Emphasis Type="Italic">Cebus apella</Emphasis>

Capuchins apply many organic materials, especially leaves, to their skin. Protection against ectoparasites is the most commonly discussed explanation for the behavior. We describe fur rubbing with carpenter ants(Camponotus rufipes) by semifree-ranging tufted capuchins(Cebus apella) in the Tietê Ecological Park, S?o Paulo, Brazil. Carpenter ants produce and secrete high concentrations of formic acid, which repels tick nymphs. Anting occurred significantly more often during months of seasonal incidence of nymphs of the tick Amblyomma cajennense, and the behavior was not related to ant-eating. We argue that anting behavior in tufted capuchins fits the hypothesis of protection against ectoparasites.     

Activity and ranging patterns in relation to fruit utilization by Brown Capuchins (Cebus apella) in French Guiana

I studied brown capuchins (Cebus apella)in primary forest in French Guiana. They displayed different feeding and ranging patterns in response to changes in fruit availability and distribution. When fruit was scarce and patchily distributed, foliage/stem feeding and invertebrate foraging was high, and capuchins limited their daily movement to <2 km, focusing on large fruit patches. When fruit was in average supply and scattered throughout the forest, the proportions of foliage/stems and invertebrates in the diet decreased, and the day range length increased to 2.8 km. When fruit was abundant and widespread, foliage/stems were rarely eaten, while invertebrate foraging increased, and. the daily locomotor distance was reduced to 2 km.     

Improving monitoring tools for spotted wing drosophila,Drosophila suzukii

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) were trapped in the field using colored plastic sphere traps coated with insect Tangle‐trap. Red and black spheres captured significantly more D. suzukii than white spheres. Translucent deli‐cup traps deployed in cherry orchards and baited with yeast, the Alpha Scents lure, or the Scentry lure captured significantly more flies than the Trécé lure and Suzukii bait; all attractants had poor selectivity for D. suzukii. No‐choice evaluations of attractants conducted in field cages corroborated the cherry orchard field study, though translucent deli‐cup traps provisioned with the yeast bait captured significantly more flies than those baited with the Alpha Scents lure. Red sphere traps baited with the Scentry lure captured 3–6× more flies than the deli‐cup trap baited with the same lure, and 3–4× more flies than the deli‐cup trap baited with yeast bait, demonstrating that a trap integrating both visual and olfactory cues is a superior tool for monitoring D. suzukii. Moreover, this simple sticky, dry trap design requires far less labor and maintenance than does a liquid‐based deli‐cup trap.     

Ant-Gathering with Tools by Captive Tufted Capuchins (Cebus apella)

We examined ant-gathering with tools by captive tufted capuchins (Cebus apella) via two experiments. In Experiment 1, we provided groups of subjects with sticks and small branches and an apparatus that accommodated the use of tools to gather ants. In Experiment 2, we sealed the apparatus with acetate and provided the same subjects with sticks and stones. Seven of 14 subjects used sticks and leaves as probes to extract ants from the apparatus. Six of them modified probes by detaching sticks from larger branches, breaking sticks into two or more pieces, and subtracting leaves and bark. Three subjects later used a stone and stick tool-set to penetrate acetate barriers and to extract ants. These results demonstrate the use of tools by Cebus to capture moving prey and are consistent with the idea that sensorimotor skills associated with the production and use of tools in primates evolved convergently in capuchins and great apes.     

Aimed Throwing as a Means of Food Transfer Between Tufted Capuchins (Cebus apella)

We examined aimed throwing as a means of food transfer in tufted capuchins (Cebus apella). We conducted this research in three phases. In Phase 1 we provided food to monkeys in one of two groups housed 1 m apart. We did not provide food to subjects in the second group. An observer recorded each instance in which a subject in the first group threw food toward one in the second group. In Phase 2 we provided a group of capuchins with food and noted each instance in which a subject threw food toward an empty cage. In Phase 3 we provided food simultaneously to two groups of capuchins and noted each instance of food-throwing between them. In Phase 1 subjects in one group threw food toward subjects in a second group, which, when provided the opportunity, did not throw food toward capuchins in the first group. Thrown food was either caught, retrieved, or lost on the test room floor. The rate of throwing decreased significantly when subjects were presented with an empty cage and when both groups of subjects were given food. We propose that psychological processes which underlie aimed throwing and food sharing came into existence through convergent evolution in large-brained, extractive foraging primates. We further speculate that although a well-developed system of exchange, based on contingent reciprocity, may occur among primates only inHomo,simpler transfer systems involving voluntary unidirectional passing of food from one individual to another appear to be more widespread among primates than previously thought and can be expressed in rather unusual circumstances such as those in this experiment.     

Delay Maintenance in Tonkean Macaques (<Emphasis Type="BoldItalic">Macaca tonkeana</Emphasis>) and Brown Capuchin Monkeys (<Emphasis Type="BoldItalic">Cebus apella</Emphasis>)

Animals commonly face choices requiring them to wait and postpone action. The ability to delay gratification is a prerequisite for making future-oriented decisions. We investigated the ability of brown capuchins (Cebus apella) and Tonkean macaques (Macaca tonkeana) to delay benefits in several experiments. In exchange tasks, subjects had to return a piece of cookie after a given time lag to obtain a larger one from an experimenter. Capuchins could wait 10–40 s and macaques 20–80 s depending on subjects and the size of rewards. Both groups were able to anticipate delay durations, but unlike macaques, capuchins discounted all sizes of reward at the same speed, meaning that their delay-maintenance was not affected by the reward size. When the subjects could give the initial piece of cookie back immediately and then wait for the return, performances increased to 10–21 min for capuchins and 21–42 min for macaques, demonstrating the role of consumption inhibition in postponing gratification. In a further task, we presented subjects with an accumulation of food pieces added at short intervals until they seized them. On average, brown capuchins could wait 33–42 s and macaques 38–72 s before seizing the rewards. Our results confirmed that brown capuchins were more impulsive than Tonkean macaques in several tasks. We did not find significant differences between the waiting performances of the Tonkean macaques and those previously reported in long-tailed macaques. The contrasting performances of macaques and capuchins might be related to their different skills in the physical and social domains.     

Capuchin monkey (Cebus apella) grips for the use of stone tools

This research examined capuchin monkey (Cebus apella) grips for the use of throwing, nut-cracking, and cutting tools. We provided subjects with stones and apparatus that accommodated the use of stones as tools. Our subjects exhibited five grips, two of which the animals used when force was the primary consideration (power grips) and three of which the animals use when accuracy of sensory judgment and instrumentation was required (precision grips). We believe that the range of contexts in which capuchins use stone tools, combined with the ability of capuchins to employ both power and precision grips as part of their tool repertoire, indicate that Cebus apella can be used to identify grips that facilitated hominid lithic technology. Am J Phys Anthropol 103:131–135, 1997. © 1997 Wiley-Liss, Inc.     

Carrying, Sharing, and Hand Preference in Tufted Capuchins (Cebus apella)

We examined the relationship among carrying, food-sharing, and hand preference in tufted capuchins (Cebus apella). The rationale was to evaluate further the use of Cebus as an alternative primate model to Pan for behavior relevant to early hominid evolution. We first examined bipedalism and food-sharing within an established social group, and then examined the direction and strength of hand preference for food carrying in an expanded sample. Several aspects of capuchin behavior warrant discussion. First, bipedal carrying and food-sharing occurred more frequently when we provided bulky foods than when we provided smaller foods. Second, food-sharing was characterized by passive tolerance, rather than active giving, between subjects. Third, subjects shared food primarily with immatures and followed a pattern of reciprocal exchange. Finally, we found no evidence for population-level hand preference for carrying. We posit that an array of behavioral similarities among Cebus, Pan, and Homo evolved through convergent processes, and in this regard capuchins can be seen as an alternative primate model to chimpanzees for the evolution of early hominid behavior.     

Growth and reproduction in captive tufted capuchins (Cebus apella)

We present data on weight and reproduction from a colony of tufted capuchins monkeys (Cebus apella) over a 12 year period. The data constitute a normative record for this species. Weight at birth averages 210 g, and infants gain weight rapidly. Females typically first conceived just after their fifth birthday, and males were fertile by 4 years, 5 months. Interbirth intervals average 576 days. Eighty-seven percent of live-born infants survived past 6 months. Three of eight live-born infants that died prior to 6 months succumbed from trauma inflicted by cage mates. Am. J. Primatol. 44:197–203, 1998. © 1998 Wiley-Liss, Inc.     

Field Anesthesia and Health Assessment of Free-ranging <Emphasis Type="Italic">Cebus capucinus</Emphasis> in Panama

Health and disease are critical factors for understanding primate evolution and for developing effective conservation and management strategies. However, comprehensive health assessments of wild primate populations are rare, in part because of the difficulty and risk of chemically immobilizing subjects to obtain the necessary biological samples. We report here the results of a health assessment, as well as the methods and drug dosages used to capture white-faced capuchins (Cebus capucinus) on Barro Colorado Island, Panama. We captured and measured 24 capuchins as part of an ongoing radiotelemetry study, and collected biological samples from 9 of them for a comprehensive health survey. Telazol® was very effective for immobilizing and capturing capuchins, although the doses we used were higher than those recommended for captive capuchins. High Telazol doses immobilized individuals quickly, ensuring that we were able to find and recover the sedated monkeys. The capuchins were generally in good condition, and had few ecto-, hemo-, or intestinal parasites. However, all but 1 of the adults had substantial dental abnormalities. In addition, 1 juvenile had indeterminate genitalia that we believe to be the result of hypospadias. Seven of the capuchins tested positive for exposure to Herpesvirus tamarinus and all individuals tested positive for exposure to Cebus cytomegalovirus. Hematology, serum chemistry, and plasma mineral levels from the wild individuals were, for the most part, comparable to those recorded for captive Cebus capucinus, and contribute to establishing baseline health values for the species.     

Vertebrate Predation and Food-Sharing in Cebus and Pan

Capuchins and chimpanzees are the only nonhuman primates apart from baboons known to prey systematically upon relatively large vertebrates. Vertebrate predation is common and well documented in Pan troglodytes, rare in Pan paniscus, and commonly reported but infrequently studied in Cebus. Food-sharing is common in both Pan species but rarely reported for wild capuchins. I present data on vertebrate predation and food-sharing by white-faced capuchins (Cebus capucinus) from ongoing field studies at Santa Rosa National Park, Costa Rica. We have observed 106 successful predation events resulting in the capture of 156 prey items during 2929 observation hr (5.35 prey per 100 hr). Squirrels and nestling coatis comprised half of the prey taken; the remainder were mainly nestling birds and eggs. Adult males took 52% of all prey and 67% of squirrels. Squirrels are actively hunted and about 65% of them are adults. I estimated that the average capuchin group kills 43–50 squirrels annually, mostly during the dry season. Capuchins hunt squirrels in groups 81% of the time, and 17% of hunts are successful. There is no evidence for cooperative hunting, but occasional collaboration is suggested. Rates of food-sharing were low (1.7 per 100 hr), and meat was the only food shared between adults. I compare predation and food-sharing in C. capucinus with published data for Pan troglodytes, primarily in Gombe and Taï National Parks. I discuss sex differences, hunting strategies, the relationship between hunting and food-sharing, and various ecological and social factors that may promote vertebrate predation in Pan and Cebus.     

Reproductive Seasonality in Female Capuchins (<Emphasis Type="Italic">Cebus capucinus</Emphasis>) in Santa Rosa (Area de Conservación Guanacaste), Costa Rica

The income-capital breeding model was developed to explain birth seasonality and reproductive strategies in female animals in relation to the abundance of food energy in the environment. An income breeder uses currently available energy and acts so as to maximize either maternal survival or weanling survival, depending on the relationship between timing of births and abundance of food energy. A capital breeder stores energy reserves for future reproductive use. Here we examined energetic influences on reproductive seasonality in a population of female white-faced capuchins (Cebus capucinus) living in a seasonal dry forest in Costa Rica. Our objectives were to determine: 1) the degree of fruiting seasonality in capuchin food trees and 2) the temporal relationship between capuchin births/conceptions and fruit abundance. Our sample included 25 yr of birth data (N = 100 births), 4 yr of capuchin fruit tree phenology data, and 18 mo of ovarian hormone data, which we used to calculate gestation lengths and estimate conception dates. Using circular statistics, we found that the mean peak in fruit abundance occurs in June, and that this population of capuchins reproduces seasonally, with 44% of births occurring within a 3-mo period (May to July, mean month = May). We propose that white-faced capuchins can be generally classified as income breeders that maximize maternal survival instead of weanling survival and that they time infant births such that the most energy expensive period of reproduction, mid-to-late lactation, occurs during the mean peak in fruit abundance.     

Activity Patterns,Home Range Size,and Intergroup Encounters in <Emphasis Type="Italic">Cebus albifrons</Emphasis> Support Existing Models of Capuchin Socioecology

Variation in ranging behavior, social organization, and feeding ecology among capuchins (Cebus spp.) is a classic example of how closely related species may be differentially adapted to their local environments. Marked differences in all 3 areas occur among Cebus spp. between the untufted capuchins (Cebus capucinus, C. olivaceous, and C. albifrons) and the tufted capuchins (C. apella, C. xanthosternos, C. nigritus, and C. libidinosus). The key socioecological distinction between the 2 groups has traditionally been that, compared with the tufted group, untufted capuchins eat more ripe foods, as befits their more gracile masticatory system; range more broadly in search of high-quality foods; and live in larger groups with more males and more agonistic interactions between groups. Here I assess how well the basic socioecological characteristics —activity budget, ranging— of previously unstudied Ecuadorian Cebus albifrons fit within this model. Few researchers have conducted studies on Cebus albifrons, despite its prominent role in the initial development of the model for socioecology of Cebus. The results of my 1-yr study of a single social group support the model’s general characterization of untufted capuchins in ranging and feeding behaviors, but also suggest that direct ecological and demographic effects, in addition to adaptation to local conditions, may explain additional variation in group size across species of Cebus.     

The Repertoire and Social Function of Facial Displays in Cebus capucinus

Systematic studies on facial displays in capuchins are limited and based mainly on studies of tufted capuchins (Cebus apella). Despite the great social-morphological variability within Cebus suggesting possible morphological and functional variations in the facial displays of different species, no study has considered thoroughly visual communication in the genus. Our aim was to describe the facial displays of white-faced capuchins and to assess their distribution and communicative function. We observed 15 captive white-faced capuchins in the Primate Centre of the Louis Pasteur University of Strasbourg, for a total of 198 h. We described the following facial displays: relaxed open-mouth, lip-smacking, open-mouth threat-face, silent bared-teeth, open-mouth silent bared-teeth, protruded-lip face, and tongue-out. We never observed the scalp-lifting display, one of the most common displays characterizing tufted capuchins. White-faced capuchins use the majority of facial displays in an affiliative or playful context; only the open-mouth threat-face display is associated with aggressive behaviors. White-faced capuchins lack ritualized signals of submission. The fact that in white-faced capuchins the silent bared-teeth display conveys only a positive message, while in tufted capuchins it signals submission as well as affiliation, supports the covariation hypothesis (Thierry 2004 Social epigenesis. In B. Thierry, M. Singh, & W. Kaummans (Eds.), Macaque societies: A Model for the study of social organization, pp. 267–294. Oxford University Press).     

Physiological status of Drosophila suzukii (Diptera: Drosophilidae) affects their response to attractive odours

An improved understanding of the biology of the invasive pest, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is critical for the development of effective management strategies. Trapping is one technique used for both detection and control; however, the efficacy of trapping can vary depending on the target insect's physiological state, its behavioural priorities and the type of attractant used in the trap. We conducted a series of caged trapping experiments and a greenhouse trapping experiment to investigate the effects of D. suzukii feeding status, age, mating status, ovipositional status and seasonal morph type on the capture rate of traps baited with fermentation odours. Starved flies were trapped at greater rates compared to fed flies; more virgin flies were trapped than mated flies; flies deprived of an oviposition substrate were trapped more frequently than flies given an oviposition substrate. It is still unclear whether age or seasonal morphology affect bait response. Lastly, a caged choice experiment investigated the relationship between female reproductive status and attraction to fermentation or fruit odours. Fermentation‐based traps captured female flies regardless of their reproductive status but, ripe fruit‐based traps were more attractive to flies with more than seven eggs. In summary, studies that use fermentation‐based traps should recognize that capture rates of D. suzukii will depend on the feeding, mating and oviposition experiences of the population; also, fruit‐based traps may better target gravid females.     

Simpler is better: fewer non‐target insects trapped with a four‐component chemical lure vs. a chemically more complex food‐type bait for Drosophila suzukii

Baits – fermented food products – are generally attractive to many types of insects, which makes it difficult to sort through non‐target insects to monitor a pest species of interest. We test the hypothesis that a chemically simpler and more defined attractant developed for a target insect is more specific and attracts fewer non‐target insects than a chemically more complex food‐type bait. A four‐component chemical lure isolated from a food bait and optimized for the spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), was compared to the original wine/vinegar bait to assess the relative responses of non‐target insects. In several field experiments in Washington State, USA, it was shown that numbers of pest muscid flies, cutworm and armyworm moths, and pest yellowjackets were reduced in traps baited with the chemical lure compared to the wine/vinegar bait. In other field experiments in the states of Washington, Oregon, and New York, numbers of non‐target drosophilid flies were also reduced in traps baited with the chemical lure relative to wine/vinegar bait. In Washington, numbers of Drosophila melanogaster Meigen and Drosophila obscura Fallen species groups and Drosophila immigrans Sturtevant were reduced in the chemical lure traps, whereas in New York, D. melanogaster and D. obscura species groups, D. immigrans, Drosophila putrida Sturtevant, Drosophila simulans Sturtevant, Drosophila tripunctata Loew, and Chymomyza spp. numbers were reduced. In Oregon, this same effect was observed with the D. melanogaster species group. Taken together, these results indicate that the four‐component SWD chemical lure will be more selective for SWD compared to fermentation baits, which should reduce time and cost involved in trapping in order to monitor SWD.     

Trap colour and aggregation pheromone dose affect the catch of western flower thrips in blackberry crops

Frankliniella occidentalis causes significant damage to berry crops in Mexico. Traps may be used for monitoring or mass-trapping thrips populations. Generally, colour traps are used for monitoring thrips, but sometimes a chemical stimulus can be added to the traps. However, there is conflicting information about what colour is the most attractive and efficient for capturing F. occidentalis. In this study, we first evaluated six colours of adhesive traps for catching F. occidentalis in blackberries grown in tunnels or in an open field. Subsequently, using the most attractive trap colour, we assessed the biological activity of neryl (S)-2-methylbutanoate and (R)-lavandulyl acetate, components of the pheromone aggregation of F. occidentalis. Finally, we examined the effect of neryl (S)-2-methylbutanoate dosage rates on the number of captured thrips. We found that blue (tunnel) and yellow (open field) followed by violet traps captured a significantly greater number of F. occidentalis compared with the white, black and green traps. Our results confirm that neryl (S)-2-methylbutanoate is the only component necessary for enhancing the performance of coloured traps. Blue and yellow traps baited with 200–400 µg of neryl (S)-2-methylbutanoate increased the capture 2.5–3 times compared to unbaited traps. In all experiments, traps captured more females than males in blackberries grown in tunnels, whereas the opposite was found in blackberries cultivated in the open field. These results constitute the first step in the development of a monitoring system for F. occidentalis in soft fruit crops in Mexico.     

Fluorescent prey traps in carnivorous plants

Carnivorous plants acquire most of their nutrients by capturing ants, insects and other arthropods through their leaf‐evolved biological traps. So far, the best‐known attractants in carnivorous prey traps are nectar, colour and olfactory cues. Here, fresh prey traps of 14 Nepenthes, five Sarracenia, five Drosera, two Pinguicula species/hybrids, Dionaea muscipula and Utricularia stellaris were scanned at UV 366 nm. Fluorescence emissions of major isolates of fresh Nepenthes khasiana pitcher peristomes were recorded at an excitation wavelength of 366 nm. N. khasiana field pitcher peristomes were masked by its slippery zone extract, and prey capture rates were compared with control pitchers. We found the existence of distinct blue fluorescence emissions at the capture spots of Nepenthes, Sarracenia and Dionaea prey traps at UV 366 nm. These alluring blue emissions gradually developed with the growth of the prey traps and diminished towards their death. On excitation at 366 nm, N. khasiana peristome 3:1 CHCl₃–MeOH extract and its two major blue bands showed strong fluorescence emissions at 430–480 nm. Masking of blue emissions on peristomes drastically reduced prey capture in N. khasiana pitchers. We propose these molecular emissions as a critical factor attracting arthropods and other visitors to these carnivorous traps. Drosera, Pinguicula and Utricularia prey traps showed only red chlorophyll emissions at 366 nm.     

Odour-baited traps influence thrips capture in proximal unbaited traps in the field

Two field experiments examined the distance over which an attractant odour of a volatile chemical could influence thrips capture in proximal traps that were without the odour. In each experiment a star‐shaped array of water traps consisted of a centre trap with or without an odour surrounded by odourless traps at 0.5, 1, 2, 5, and 10 m in eight equally spaced radial arms 45° apart. Experiments ran for 47 h (centre trap: ethyl nicotinate) or 7 h (centre trap: ethyl isonicotinate). Each had four replicates. With ethyl nicotinate, more thrips were trapped in the centre‐baited traps than in the unbaited centre traps (63×, 7×, 98× and 200× for total thrips, Thrips tabaci Lindeman ♀, and Thrips obscuratus Crawford ♀and ♂, respectively) (Thysanoptera: Thripidae). More total thrips and T. tabaci♀ were trapped in the centre traps baited with ethyl isonicotinate than in unbaited centre traps (21× for both). For ethyl nicotinate, numbers of T. obscuratus in unbaited traps downwind from the baited centre trap declined by 50% within 0.4 m (♀) and 2 m (♂) and by 95% within 3 m (both ♀ and ♂) based on model predictions. For ethyl isonicotinate, numbers of T. tabaci in unbaited traps downwind from the baited centre trap declined by 50% within 1.3 m and by 95% within 10 m based on model predictions. Wind direction was an important factor in the degree and direction of thrips capture with the highest thrips capture downwind from the centre trap with odour. There was no increase in numbers of T. tabaci in any traps without odour in the ethyl nicotinate‐centred array. Differences in trapping patterns between thrips species and odours indicated that there were thrips species–odour specific interactions. Experiments examining differences between traps with and without a thrips attractant odour need to be designed very carefully to ensure meaningful results especially in enclosed and/or low‐wind indoor situations.