Male influence on oestrous cycles in female woolly opossum (Caluromys philander)

Plasma progesterone concentrations and the occurrence of oestrous cycles were studied in isolated woolly opossums subsequently subjected to male influences during a 40-day period. Pairing (N = 48) or exposure to male urine (N = 15) resulted in all females exhibiting oestrous during the stimulation phase, providing evidence that the activation of ovarian activity in the woolly opossum involves pheromonal cues from males. The latency of occurrence of oestrous in stimulated females depended upon their sexual state before male stimulation. In anoestrous females, the mean latency was 20.7 +/- 0.9 days (N = 35), a value which agrees with the duration of the follicular phase. In females which first entered oestrous before male stimulation, the latency of induced oestrous was inversely correlated to the date of occurrence of the previous oestrous. The inter-oestrous interval was normal (38.1 +/- 1 days, N = 5) when females were in oestrous at the beginning of male stimulation. In contrast, the inter-oestrous interval was significantly shortened (28.7 +/- 2 days, N = 7) or lengthened (51.1 +/- 1.7 days, N = 16) depending on whether females were in the luteal or follicular phases at the beginning of male stimulation. During pairing several females became pregnant and gave birth 24 +/- 0.9 days (N = 13) after copulation. In the woolly opossum, the response to male influences involves mechanisms similar to those observed in eutherians and results in enhancement and synchronization of oestrous cycles in females. Pheromonal interactions could play an important role in synchronizing oestrous cycles in wild females during the dry season, a period when animals regroup to feed on spatially localized food resources.     

Activity and ranging patterns of Colombian woolly monkeys in north-western Amazonia

In this study, I revise three aspects of the socioecology of woolly monkeys (genus Lagothrix) that might give us a better understanding of the patterns found in this species: (1) the association between temporal variation in fruit abundance and diet, activity, and ranging patterns; (2) the individual trade-offs associated with living in small or large groups, and (3) the relationship between social dominance and foraging success. Using behavioral and ecological data collected during 3 years in Tinigua Park, Colombia, I found that woolly monkeys tend to avoid open-degraded forests, where fruit production is generally lower than it is in mature forests. Diet and activity budgets were highly associated with temporal patterns of fruit production. Daily path length was positively correlated with group size and monthly fruit abundance, and negatively correlated with habitat quality. I found differences in activity budgets and the diet preferences of different age/sex classes. For example, adult males rest more and juveniles play more than other classes. Juveniles and adult females without infants look for arthropods more often than adult males and females with young infants, who showed the highest frequencies of fruit feeding. Dominant adult males were not consistently the most efficient foragers on fruits according to two different indexes. Most of these results are consistent with the expectations from strong intra-group competition for resources. However, females with infants received benefits during feeding similar to those of dominant adult males, which may be mediated by differential aggression from males to other group members (juveniles and females without infants).     

Nitrogen requirements of the didelphid marsupial Caluromys philander

The use of fruit-based diets by a small arboreal marsupial, the woolly opossum (Caluromys philander) was studied to elucidate the mechanisms used to compensate for a low dietary protein concentration. The passage of a liquid phase digesta marker (Cr-EDTA) through the gut was significantly faster when animals were fed a diet containing 0.45% N compared to that measured on a diet containing 0.90% N. The size of the gut of the two groups was similar except that the caecum of animals fed 0.45% N was significantly larger than in those animals fed 0.90% N. Animals fed a diet of 0.45% N ate significantly more food than those fed higher levels of nitrogen but there was no significant difference in the dry matter digestibility of the diet. The maintenance nitrogen requirement of the animals was 176 mg dietary N or 146 mg truly digestible nitrogen per kg metabolic body mass, with low losses of non-dietary faecal nitrogen being notable. There was no significant difference between diets in any measured parameter of urea metabolism and all animals recycled between 60% and 80% of the endogenously synthesised urea. Accepted: 22 March 2000     

Origins of primate locomotion: gait mechanics of the woolly opossum

The locomotion of primates differs from that of other mammals in three fundamental ways. During quadrupedal walking, primates use diagonal sequence gaits, protract their arms more at forelimb touchdown, and experience lower vertical substrate reaction forces on their forelimbs relative to their hindlimbs. It is widely held that the unusual walking gaits of primates represent a basal adaptation for movement on thin, flexible branches and reflect a major change in the functional role of the forelimb. However, little data on nonprimate arboreal mammals exist to test this notion. To that end, we examined the gait mechanics of the woolly opossum (Caluromys philander), a marsupial convergent with small-bodied prosimians in ecology, behavior, and morphology. Data on the footfall sequence, relative arm protraction, and peak vertical substrate reaction forces were obtained from videotapes and force records for three adult woolly opossums walking quadrupedally on a wooden runway and a thin pole. For all steps recorded on both substrates, woolly opossums always used diagonal sequence walking gaits, protracted their arms beyond 90 degrees relative to horizontal body axis, and experienced peak vertical substrate reaction forces on forelimbs that were significantly lower than on hindlimbs. The woolly opossum is the first nonprimate mammal to show locomotor mechanics that are identical to those of primates. This case of convergence between primates and a committed fine-branch, arboreal marsupial strongly implies that the earliest primates evolved gait specializations for fine-branch locomotion, which reflect important changes in forelimb function.     

Activity budgets of woolly spider monkeys,or muriquis (Brachyteles arachnoides)

One group of woolly spider monkeys, or muriquis (Brachyteles arachnoides), was observed from June 1983 through July 1984 at Fazenda Montes Claros, Minas Gerais, Brazil. The study subjects spent an average of 49% of their daylight time resting, 29% traveling, and 19% feeding. They shifted their diurnal schedule of activities in response to seasonal changes in temperature and rainfall. The activity budgets of adult males and females were similar. However, a comparison of three adult females in different reproductive conditions revealed that the lactating female spent a greater proportion of time feeding than did both the pregnant and nonreproductive females. Intraspecific differences in group size and diet appear to be important to understanding differences in the activity budgets of Brachyteles. Differences between locomotion patterns of woolly spider monkeys and sympatric howler monkeys may explain activity budget differences based on group size and diet.     

Social Behavior,Reproductive Strategies,and Population Genetic Structure of <Emphasis Type="Italic">Lagothrix poeppigii</Emphasis>

For species of primates in which females emigrate, we would expect males within groups to be related to one another. Kin selection theory suggests that these males should associate preferentially with one another, be more affiliative and cooperative with one another than females are, and compete less overtly with one another over reproductive opportunities than males in female philopatric taxa do. Precisely these patterns of social behavior characterize well-studied populations of 2 of the 3 atelin primate genera: spider monkeys (Ateles) and muriquis (Brachyteles). For the third atelin genus, Lagothrix, patterns of intragroup social behavior have been less well-documented. We studied the social and reproductive behavior of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in Ecuador during a one-year observational study and subsequently used molecular techniques to investigate population genetic structure and dispersal patterns for this taxon. Among adult male woolly monkeys, both affiliative and agonistic interactions were rare, and males were seldom in close proximity to one another. Relationships among male woolly monkeys are best characterized as tolerant, especially in the context of mating wherein direct competition among males was minimal despite the fact that females mated with multiple males. Relationships among females were likewise generally tolerant but nonaffiliative, though females often directed harassment towards copulating pairs. Affiliative interactions that did occur among woolly monkeys tended to be directed either between the sexes—primarily from female to male—or from younger towards older males, and the proximity partners of females tended to be members of the opposite sex. These results suggest that bonds between the sexes may be more important than same-sex social relationships and that direct female-female competition is an important feature of woolly monkey reproductive biology. Our genetic results indicate that, as in other atelins, dispersal by females is common, but some male dispersal likely occurs as well. In some but not all groups we studied, nonjuvenile males within social groups were more closely related to one another on average than females were, which is consistent with greater male than female philopatry. However, differences in these patterns among our study groups may reflect local variation in dispersal behavior.     

Scent marking in two western Amazonian populations of woolly monkeys (Lagothrix lagotricha)

We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially confounding variable of ripe fruit availability was controlled for. In woolly monkeys, overt male-male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity.     

Ecological strategies of woolly monkeys (Lagothrix lagotricha) at Tinigua National Park,Colombia

Information on the use of space, activity patterns, diet, and social interactions were recorded for a group of woolly monkeys (Lagothrix lagotricha) during 13 months at Tinigua National Park, Macarena, Colombia. In this region, fruit abundance changes throughout the year with a peak during March–April (beginning of the rainy season) and less fruit during September-November (end of rainy season). Woolly monkeys spent most of their time in mature forest where fruit abundance is higher than in opendegraded or flooded forests. Changes in habitat used by monkeys were coupled with changes in fruit supply across vegetation types. On an annual basis, woolly monkeys spent 24% of point samples locomoting, 36% resting, 36% feeding, and 4% on other activities. However, these proportions varied across the year depending on fruit availability. Based on instantaneous samples, the diet consisted mostly of fruits (60%), arthropods (23%), vegetative parts and flowers (17%), and other items (1%). Non-lactating females and juveniles spent more time eating insects than adult males and lactating females; however, significant differences between classes were detected only during the period of fruit scarcity. These differences are probably due to the high extent to which non-lactating females and juveniles were excluded from fruiting trees by males. The high proportion of arthropods in their diet is unusual for primates with large body size and is a possible factor influencing group cohesiveness in woolly monkeys. © 1994 Wiley-Liss, Inc.     

Feeding and egg distribution studies of Heringia calcarata (Diptera: Syrphidae), a specialized predator of woolly apple aphid (Homoptera: Eriosomatidae) in Virginia apple orchards

Predation by the aphidophagous syrphid fly Heringia calcarata (Loew) on woolly apple aphid, Eriosoma lanigerum (Hausmann), was studied in the laboratory and in Virginia apple orchards. Feeding studies compared the prey suitability of three temporally sympatric aphid pests of apple: spirea aphid, Aphis spiraecola Patch; rosy apple aphid, Dysaphis plantaginea (Passerini); and woolly apple aphid. Significantly more H. calcarata larvae survived and completed development on a pure diet of woolly apple aphid than on rosy apple aphid, and none survived on spirea aphid. Final larval weights were significantly greater, and the larval developmental period was significantly shorter on woolly apple aphid than on rosy apple aphid, but neither the duration of pupal development nor adult weight differed between diets. H. calcarata larvae consumed an average of 105 woolly apple aphids during their development. Na?ve, neonate larvae given access to all possible pair combinations of woolly apple aphid, rosy apple aphid, and spirea aphid consumed significantly more woolly apple aphids in all pairings that included woolly apple aphid. When given a choice of rosy apple aphid and spirea aphid, significantly more rosy apple aphids were consumed. Weekly counts of syrphid eggs found in woolly apple aphid, rosy apple aphid, and spirea aphid colonies collected from apple trees showed that two generalist hover fly predators, Eupeodes americanus (Wiedemann) and Syrphus rectus Osten Sacken, were present in colonies of all three aphid species and that E. americanus was the most abundant syrphid predator in A. spiraecola and D. plantaginea colonies. H. calcarata eggs were found only in woolly apple aphid colonies and were more abundant there than E. americanus and S. rectus. These data suggest that H. calcarata is a specialized predator of woolly apple aphid in the apple ecosystem in Virginia.     

Habitat,diet, and activity patterns of free-ranging woolly spider monkeys (Brachyteles arachnoides E. Geoffroy 1806)

Results of a 10-month study of the ecology and behavior of free- ranging woolly spider monkeys (Brachyteles arachnoides)in Brazil show that these animals are strongly folivorous. Leaf-eating accounted for more than 50% of the total feeding time in all samples but one and accounted for more than 80% of the total feeding time in three samples. Mature foliage was routinely eaten. Woolly spider monkeys consistently spend more than 50% of each day quietly resting and sleeping. Animals travel little except when actively feeding and show low levels of social interaction. Such an activity profile suggests that woolly spider monkeys may often be living near the limits of their energetic resources. The social organization of the species is unusual for a folivorous primate in that small groups of females and associated immature animals confine their activities to discrete home-range areas, whereas males are itinerant, traveling over the home ranges of various female groups. Animals sharing a common home-range area show no permanent daily pattern of association other than that of mother-dependent offspring. Foraging alone or with few conspecifics should maximize each individual’s returns from foraging by minimizing the day range that must be traveled each day to locate foods while simultaneously lowering interference competition for higher-quality dietary resources.     

The hormonal control of birth behavior in the gray short-tailed opossum (Monodelphis domestica)

In all major groups of Australian marsupials, prostaglandin F2alpha (PGF) or oxytocin injection initiates birth behavior in adult females, adult males and pouch young. Because inhibitors of PGF synthesis block this initiation, oxytocin may activate birth behavior via the stimulation of PGF synthesis. In this study, the role of PGF and oxytocin in the activation of birth behavior was examined in an American marsupial, the gray short-tailed opossum (Monodelphis domestica). Adult male and female gray opossums were given PGF, oxytocin, or saline (control) before behavioral observation. On the next day, the animals in the oxytocin group were injected with the PGF inhibitor flunixin meglumide (Finadyne, Schering Corp., U.S.A.) before oxytocin reinjection and behavioral observation. Both males and females showed birth behavior in response to PGF but only females responded to oxytocin. There was no significant difference in the latency of response of females to oxytocin alone versus response to oxytocin after receipt of the PGF inhibitor. These results suggest that, in contrast to Australian species, in this American marsupial, oxytocin initiates birth behavior only in females and does not operate via stimulation of prostaglandin secretion.     

Seed dispersal by woolly monkeys (Lagothrix lagothricha) at Tinigua National Park, Colombia: dispersal distance, germination rates, and dispersal quantity

The purpose of this study was to describe seed dispersal patterns of woolly monkeys (Lagothrix lagothricha) in terms of dispersal quantity and two factors related to dispersal quality: germination rates of dispersed seeds and the distance of dispersal to parental trees. The possible influence of retention time, travel distance, seed size, activity patterns, and fruit abundance on dispersal distance was also analyzed. Observations on activity, diet, daily movements, and seed dispersal were made on focal individuals of a group of woolly monkeys at a tropical rain forest in Tinigua National Park (Colombia). Sixty hours of focal samples per month were completed during 1 year. A total of 753 depositions were collected during the study. Each dropping contained seeds from an average of 2.68 different species (range 0 to 9). Collected depositions contained an underestimated total of 50,168 seeds (>1 mm). Given a population density of 30 individuals/km2, the woolly monkeys in the study area disperse more than 25,000 seeds/km2/day. These seeds belong to 112 different plant species. Germination rates of dispersed seeds are usually similar or higher than those of non-swallowed seeds. It was possible to determine dispersal distance in 264 cases when the focal animal was continuously followed from ingestion at the parental tree to deposition. Only 1% of these depositions landed in close proximity (<15 m) of the parental tree. It was very common that the droppings were deposited between 100 and 500 m from the parent tree, and up to 1.5 km. Higher retention times and longer travel distances were not correlated with increased dispersal distance. Two main reasons for this result were the prolonged and variable passage rates (avg=11.2 hr+/-6.5 SD.) and the circuitous routes of monkeys in this forest.     

Diet and Feeding Ecology of Woolly Monkeys in a Western Amazonian Rain Forest

I investigated the diet and feeding ecology of two social groups of woolly monkeys (Lagothrix lagotricha poeppigii) in Yasuní National Park, Ecuador between April 1995 and March 1996. Woolly monkeys in Yasuní were predominantly frugivorous, with fruits comprising ca. 77% of the yearly diet; the next most common food type in the diet was insect and other animal prey. The fruit diet of woolly monkeys in Yasuní is the most diverse yet recorded for any ateline primate, including spider monkeys (Ateles), which are often regarded as ripe fruit specialists: 208 distinct morphospecies of fruits were consumed by woolly monkeys either during the study or during several preceding months of pilot work. Nonetheless, close to one-third of the yearly diet came from just 3 plant genera—Inga, Ficus, and Spondias—and only 20 genera each contributed to 1% of the diet. For one study group, the proportion of ripe fruit in the diet each month was correlated with the habitat-wide availability of this resource, a pattern evidenced by several other ateline species. However, the relationship was not apparent in the second study group. The modal party size for feeding bouts on all food types was a single monkey, and, contrary to reports for other atelines, neither feeding party size nor the total number of feeding minutes that groups spent in food patches was well predicted by patch size. Both results highlight the independent nature of woolly monkey foraging. Given that woolly monkeys and closely-related spider monkeys focus so heavily on ripe fruits, their very different patterns of social organization are intriguing and raise the question of just how their ecological strategies differ. Two important differences appear to be in the use of animal prey and in the phytochemical composition of the ripe fruits that they consume: spider monkeys rarely forage for animal prey, and woolly monkeys seldom consume the lipid-rich fruits that are an important part of spider monkey diets.     

Does sexual segregation occur during the nonbreeding period? A comparative analysis in spatial and feeding ecology of three Calonectris shearwaters

Sexual segregation (SS) is widespread among animal taxa, with males and females segregated in distribution, behavior, or feeding ecology but so far, most studies on birds have focused on the breeding period. Outside this period, the relevance of segregation and the potential drivers of its persistence remain elusive, especially in the marine environment, where animals can disperse over vast areas and are not easily observed. We evaluated the degree of SS in spatio‐temporal distribution and phenology, at‐sea behavior, and feeding ecology during the nonbreeding period among three closely related shearwaters: Scopoli's, Cory's, and Cape Verde shearwaters (Calonectris diomedea, C. borealis, and C. edwardsii, respectively). We tracked 179 birds (92 males and 87 females) from 2008 to 2013 using geolocation‐immersion loggers and collected the 13th secondary remige (molted in winter) for stable isotope analyses as a proxy of trophic level and diet. The global nonbreeding distribution did not differ between sexes for the three species, but one specific nonbreeding area was visited only by males. Cory's shearwater males remained in areas closer to the colony in a larger proportion compared to females and returned earlier to the colony, probably to defend their nests. Males presented a slightly lower nocturnal flying activity and slightly (but consistently) higher isotopic values of δ¹³C and δ¹⁵N compared to females. These differences suggest subtle sexual differences in diet and a slightly higher trophic level in males, but the extent to which sexual dimorphism in bill size can determine them remains unclear. Our study showed that SS in ecological niche in seabirds can persist year‐round consistently but at a different extent when comparing the breeding and nonbreeding periods. Based on our findings, we propose that SS in these seabird species might have its origin in an ecological specialization derived from the different roles of males and females during reproduction, rather than from social dominance during the nonbreeding period.     

Footfall patterns and interlimb co-ordination in opossums (Family Didelphidae): evidence for the evolution of diagonal-sequence walking gaits in primates

Most primates typically use a diagonal-sequence footfall pattern during walking. This footfall pattern, which is unusual for mammals, is believed to have originated in ancestral primates in association with the use of grasping extremities for movement and foraging on thin, flexible branches. This theory was tested by comparing gait parameters between the grey short-tailed opossum Monodelphis domestica and the woolly opossum Caluromys philander , two didelphid marsupials that are strongly differentiated in grasping morphology of the extremities and in their reliance on foraging strategies involving thin branches. One hundred and thirty gait cycles were analysed quantitatively from videotapes of subjects moving quadrupedally on a runway and on poles of different diameters (7 and 28 mm). Duty factor (i.e. duration of the stance phase as a percentage of the stride period) for the forelimb and hindlimb, as well as diagonality (i.e. phase relationship between the forelimb and hindlimb cycles), were calculated for each of these symmetrical gait cycles. We found that the highly terrestrial Monodelphis , like most other non-primate mammals, relies primarily on lateral-sequence walking gaits on both runway and poles, and has relatively higher forelimb duty factors. Like primates, the highly arboreal Caluromys uses primarily diagonal-sequence walking gaits on the runway and pole, with relatively higher hindlimb duty factors and diagonality. The fact that the woolly opossum, a marsupial with primate-like feet that moves and forages mainly on thin branches, uses primarily diagonal-sequence gaits when walking supports the view that primate gaits evolved to meet the demands of locomotion on narrow supports. This also demonstrates the functional role of a grasping foot, in association with relatively higher hindlimb duty factors, protraction, and substrate reaction forces, in the production of such walking gaits.     

Ranging behavior and foraging ecology of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in Yasuní National Park,Ecuador

In a year-long study, I investigated the ranging behavior of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in a terra firma rainforest in Yasuní National Park, Ecuador, and examined the relationship between ranging, diet, food availability, and food patch use for this population. In Yasuní the total home range sizes for two social groups were 124 and 108 ha, which are much smaller than has been reported previously for Lagothrix elsewhere in its geographic distribution. The mean yearly day range estimates for these same groups were 1,792 m and 1,878 m, which are well within the range of variation previously reported. Ranging behavior was not correlated with the current habitat-wide abundance of ripe fruit, which comprises 76.3% of the yearly diet for this population, but was associated with one measure of likely insect prey abundance and with the availability of immature fruits, a minimal part of the diet. Specifically, one study group moved significantly greater distances during months of high likely insect prey abundance and when immature fruits were abundant. The second study group also traveled farther when likely insect prey abundance was high and when immature fruits were abundant, although the latter relationship only approached significance. This group also devoted significantly more of its daily activity budget to travel during these times. These results indicate that variation in ripe fruit abundance makes no meaningful contribution to explaining variation in ranging behavior for this population of woolly monkeys. Instead, the results raise the possibility that some aspects of the ranging behavior of frugivorous primates may be related to the availability of alternative food sources, such as animal prey, or to monitoring the phenological status of important fruit trees, rather than simply reflecting the degree of intragroup feeding competition.     

Besnoitia darlingi (Brumpt, 1913) in Panama

SYNOPSIS. Besnoitia darlingi (Brumpt, 1913) Mandour, 1965 has been rediscovered in the common opossum Didelphis marsupialis in the Republic of Panama. A strain (D3) has been established in laboratory white mice. Proliferative crescents of the D3 strain are 6.1 (range 6.0-9.0) by 2.1 (range 1.7-4.0).
Mouse-adapted B. darlingi produced acute, fatal infections in white mice, hamsters, 14 marmosets ( Saguinus geoffroyi ), 2 squirrels ( Sciurus variegatoides and S. granatensis ), a woolly opossum ( Caluromys derbianus ) and a four-eyed opossum ( Philander opossum ) It probably produced chronic infections (cysts) in 2 wild-caughtopossums ( Didelphis marsupialis ) and one lizard ( Ameiva ameiva ). Animals in which induced infection could not be found after inoculation with trophozoites of mouse-adapted B. darlingi were: 2 adult and 2 new-born guinea pigs, laboratory rats, 1 night monkey ( Aotus trivirgatus ), 2 rhesus monkeys ( Macacca mulatta ), one iguana ( Iguaanaiguana ) and 2 baby caimans ( Caiman sclerops ).     

Effects of female feeding regime in a sexually cannibalistic mantid: fecundity,cannibalism, and male response in Stagmomantis limbata (Mantodea)

1. Female feeding regime exhibited a cascade of effects on reproductive biology and behaviour in the mantid Stagmomantis limbata (Hahn). 2. Well‐fed females (High diet) consistently attained greater body mass, thicker abdomens, and higher fecundity than food‐limited females (Low diet) in four annual generations. Dorso‐ventral abdominal thickness strongly correlated with fecundity. 3. In an experiment in captivity, Low diet females were more likely to cannibalize males than High diet females. 4. High diet females attracted more males than Low diet females in several contexts. In terms of long‐range attraction, caged High diet females attracted more males in the field. In terms of short‐range attraction, males preferentially mounted and copulated with High diet females in captive paired choice trials. In naturally‐occurring pairs in the field, a preference for females with thick abdomens was evident. These results point to two possible explanations: male choice for well‐fed females and state‐dependent female pheromone emission. 5. Two years of field data indicate considerable variation in female feeding success, as measured by abdominal thickness. Average feeding success in nature appears to be relatively high, when comparing the rate of abdominal expansion in the field to captive females maintained on High diets. 6. In the field, nearly all mounts and copulations occurred in September in both years, when female feeding success is expected to be high. If mating activity occurs during a window of high female feeding success, so as to reduce the risk of cannibalism for males, then the female feeding regime may be implicated in the phenology of mating activity in cannibalistic species.     

Effects of different protein concentrations on longevity and feeding behavior of two adult populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae)

The effects of protein intake on two adult male and female populations of Ceratitis capitata Wiedemann were assessed. One population consisted of flies reared for twenty years in the laboratory (Lab-pop); the other population consisted both of flies reared in the laboratory for approximately fifteen years and of the periodically introduced wild flies (Hybrid-pop). Three diets were tested: a no-yeast diet and two diets containing yeast (protein source) at the concentrations 6.5 g or 1.5 g per 100 ml diet. The parameters analyzed were: adult longevity, diet intake with and without yeast, and discrimination threshold for yeast. Protein intake increased Lab-pop adult longevity and did not affect longevity of the Hybrid-pop. Longevity in each population was similar for males and females fed on the same diet. Food behavior were similar for male and female adults of both populations; all preferred diets containing protein (yeast). Males and females in both populations ingested similar amounts of each diet. The discrimination threshold for yeast was similar for all males (0.5 g yeast/100 ml diet); Lab-pop females were able to detect the presence of smaller quantities of yeast in their diet, thus having a higher discrimination capacity (0.4 g/100 ml diet) as compared to the Hybrid-pop females (0.6 g/ 100 ml diet).