Large-seeded Fruits Research Articles

Feeding ecology of the Red-and-green Macaw (Ara chloropterus; Gray 1859) in a habitat mosaic from Cerrado.

In the Brazilian Cerrado, the Red-and-green Macaw (Ara chloropterus) populations are facing an accelerated rate of habitat loss. Despite this, their feeding areas and primary food sources remain poorly understood. In this study, I assessed the relationship between the diet of the Red-and-green Macaw and available food resources in a habitat mosaic from the fragmented Cerrado in Mato Grosso do Sul State, Brazil. Red-and-green Macaws fed on 20 native and five exotic species, mainly in dry habitats (Cerrado, dry forest, and an urban area along the Maracaju Cliffs) during the dry season, while year-round foraging in the riparian vegetation (Aquidauana River and streams). Then, the number of feeding macaws paralleled variations in food abundance and diversity, besides the number of food species. On the other hand, by using a wide variety of abundant foods, macaws' diet breadth presented high values throughout the year. The seasonal consumption of large-seeded fruits across the habitat mosaic displayed a gradient ranging from the urban area to dry habitats, along which macaws ate from exotic to Cerrado species. In this respect, Terminalia catappa seeds and Mangifera indica fruit pulp were important for Red-and-green Macaws in the urban area during the wet season, while Caryocar brasiliense seeds comprised the same in the Cerrado. At this site, both Dipteryx alata and Buchenavia tomentosa seeds composed much of the Red-and-green Macaws' diet during the dry season. Between those habitats, in the watercourse vegetation, macaws frequently foraged on palm fruits across seasons. Therefore, throughout the year, the abundance and variety of food resources strongly influenced the number of foraging Red-and-green Macaws across the habitat mosaic. Understanding the effect of varying seed availability on the spatial and temporal abundance patterns of Red-and-green Macaws, which primarily feed on large-seeded species, is central to developing effective conservation strategies. Due to the accelerated habitat loss, the Maracaju Cliffs emerge as crucial for the Red-and-green Macaw among the Cerrado remnants of Mato Grosso do Sul.

Does frugivory in Citharexylum solanaceum (Verbenaceae) drive nomadism in the Ipanema bat Pygoderma bilabiatum (Chiroptera: Phyllostomidae)?

Neotropical bats are recognized as effective seed dispersers, especially of small-seeded pioneer plants during early stages of forest regeneration. There had been few reports on the ecology of the bat Pygodermabilabiatum (Wagner, 1843), which appears to be mainly frugivorous and to undertake vertical migrations in Brazil. Our analyzes of fecal samples of P.bilabiatum specimens captured in mist nets and direct observations of their feeding behavior on Citharexylumsolanaceum Cham. fruits in a mosaic of restored forests and forest fragments in southeastern Brazil constitute one of the few records of consumption of large-seeded fruits by P.bilabiatum, and indicate that it may be an important disperser for large-seeded plants. We found evidence that the temporal availability of those fruits may influence the movement ecology of those bats.

Low host specificity and abundance of frugivorous lepidoptera in the lowland rain forests of Papua New Guinea.

We studied a community of frugivorous Lepidoptera in the lowland rainforest of Papua New Guinea. Rearing revealed 122 species represented by 1,720 individuals from 326 woody plant species. Only fruits from 52% (171) of the plant species sampled were attacked. On average, Lepidoptera were reared from 1 in 89 fruits and a kilogram of fruit was attacked by 1.01 individuals. Host specificity of Lepidoptera was notably low: 69% (33) of species attacked plants from >1 family, 8% (4) fed on single family, 6% (3) on single genus and 17% (8) were monophagous. The average kilogram of fruits was infested by 0.81 individual from generalist species (defined here as feeding on >1 plant genus) and 0.07 individual from specialist species (feeding on a single host or congeneric hosts). Lepidoptera preferred smaller fruits with both smaller mesocarp and seeds. Large-seeded fruits with thin mesocarp tended to host specialist species whereas those with thick, fleshy mesocarp were often infested with both specialist and generalist species. The very low incidence of seed damage suggests that pre-dispersal seed predation by Lepidoptera does not play a major role in regulating plant populations via density-dependent mortality processes outlined by the Janzen-Connell hypothesis.

Long-distance seed dispersal by straw-coloured fruit bats varies by season and landscape

On-going fragmentation of tropical forest ecosystems and associated depletion of seed dispersers threatens the long-term survival of animal-dispersed plants. These threats do not only affect biodiversity and species abundance, but ultimately ecosystem functions and services. Thus, seed dispersers such as the straw-coloured fruit bat, E. helvum, which traverse long distances across fragmented landscapes, are particularly important for maintaining genetic connectivity and colonizing new sites for plant species. Using high-resolution GPS-tracking of movements, field observations and gut retention experiments, we quantify dispersal distances for small- and large-seeded fruits foraged by E. helvum during periods of colony population low (wet season) and high (dry season) in an urban and a rural landscape in the forest zone of Ghana. Gut passage time averaged 116 min (range 4–1143 min), comparable to other fruit bats. Movements were generally longer in the urban than in the rural landscape and also longer in the dry than in the wet season. As the majority of seeds are dispersed only to feeding roosts, median dispersal distances were similar for both large (42–67 m) and small (42–65 m) seeds. However, small seeds were potentially dispersed up to 75.4 km, four times further than the previous maximum distance estimated for a similar-sized frugivore. Maximum seed dispersal distances for small seeds were almost twice as long in the rural (49.7 km) compare to the urban (31.2 km) landscape. Within the urban landscape, estimated maximum dispersal distances for small seeds were three times longer during the dry season (75.4 km) compared to the wet season (22.8 km); in contrast, distances in the rural landscape were three times longer in the wet season (67 km) compared to the dry season (24.4). Dispersal distances for large seeds during the dry season (551 m) in the rural landscape were almost twice that in the wet season (319 m). We found no influence of food phenology on dispersal distances. The maximum likelihood for seed dispersal beyond feeding roosts (mean distance from food tree 263 m) was 4.7%. Small seeds were dispersed over even longer distances, >500 and >1000 m, with a likelihood of 3.0 % and 2.3 % respectively. Our data show that E. helvum retains ingested seeds for very long periods and may traverse large distances, probably making it an important long distance seed disperser in tropical Africa. We suggest E. helvumis important for ecosystem functioning and urge its conservation.

Frugivorous weevils are too rare to cause Janzen–Connell effects in New Guinea lowland rain forest

Abstract:A community of frugivorous weevils was studied by quantitative rearing of 57 weevil species represented by 10485 individuals from 326 woody plant species in lowland rain forest in Papua New Guinea. Only fruits from 35% of plant species were attacked by weevils. On average, weevils were reared from only 1 in 33 fruits and 1 kg of fruit was attacked by 2.51 individuals. Weevil host specificity was relatively high: 42% of weevil species fed on a single plant genus, 19% on a single plant family and only 16% were reared from more than one family. However, monophagous specialists represented only 23% of all reared individuals. The average 1 kg of fruits was infested by 1.84 individuals of generalist weevils (feeding on allogeneric or allofamilial host species), 0.52 individual of specialists (feeding on a single or several congeneric species), and 0.15 individual of unknown host specificity. Large-seeded fruits with thin mesocarp tended to host specialist species whereas those with thick, fleshy mesocarp were often infested with both specialists and generalists. Weevils tended to avoid small-seeded, fleshy fruits. The low incidence of seed damage (3% of seeds) suggests that weevils are unlikely to play a major role in regulating plant populations via density-dependent mortality processes outlined by the Janzen–Connell hypothesis.

Fleshy fruit characteristics in a temperate deciduous forest of Japan: how unique are they?

This study investigated the fleshy fruit characteristics of 28 woody species in a Japanese temperate forest where large sedentary seed-dispersing mammals are present. We tested whether the findings in previous studies in temperate forests of Europe and North America are universal or not. Results have suggested that fruits of all species were eaten both by birds and mammals except for four species with larger fruits, which were eaten only by mammals. A gradient was found from a syndrome characterized by small, oily, and large-seeded fruits to a syndrome characterized by large, succulent, non-oily, and small-seeded fruits. The sizes and colors of the fruits were not conspicuously different from previous findings in Europe and North America. On the other hand, nitrogen and lipids in the fleshy part did not show seasonally increasing trends, or even seasonally decreasing trends in terms of dry weight. This result, suggesting the absence of community-level adaptation of fruit traits to migratory bird dispersers, contrasted with findings in Europe and North America. Large sedentary arboreal or tree-climbing mammals may have a greater effect on the evolution of fruit-disperser relations than opportunistic migratory birds.

The effect of seed packaging on digestion and food preference by Purple-crested (Gallirex porphyreolophus) and Knysna (Tauraco corythaix) Turacos

Avian frugivores may select fruit based on their seed loads and pulp-to-seed ratios, and this may have important implications for their role as seed dispersal agents. Consequently, the effect of different seed packaging was investigated in two relatively large South African frugivores, Knysna (Tauraco corythaix) and Purple-crested (Gallirex porphyreolophus) Turacos. Small-seeded artificial fruits containing on average five black plastic beads (2.24 mm diameter) and large-seeded artificial fruits containing on average one single black plastic bead (3.85 mm diameter) were used to investigate minimum transit times and food preference. The total seed volumes of the two fruits were on average approximately equal (29.42 and 29.88 mm3 for small- and large-seeded fruits, respectively). Bead minimum transit times ranged from 38 to 45 min for Knysna Turacos and 36 to 50 min for Purple-crested Turacos, with faster minimum transit times on the small-seeded diet. Pulp minimum transit times ranged from 25 to 39 min for Purple-crested Turacos and 34 to 40 min for Knysna Turacos. Purple-crested Turacos had significantly shorter pulp minimum transit times on the large-seeded than the small-seeded diet, whereas Knysna Turacos showed no significant difference between diets. Knysna Turacos preferred the small-seeded to the large-seeded artificial fruits, whereas Purple-crested Turacos showed no preference for either diet. Further studies on avian dispersers will contribute to a greater understanding of their evolutionary relationship with fruiting plants. In particular, future studies establishing suitable seed sizes and volumes for use in determining the effect of seed packaging on larger birds are required, and studies looking at seed packaging of indigenous forest fruit and the effects of seed packaging on digestion and food preference in indigenous avian frugivores may give insight into the role of avian frugivores as fruit consumers and seed dispersers.

Comparative analysis of wing morphology, flight behaviour, and habitat use in flying foxes (Genus: Pteropus)

We compared morphological indices, flight behaviour, and foraging and habitat use in two sympatric species of flying foxes, the insular flying fox (Pteropus tonganus) and the Samoan flying fox (Pteropus samoensis), to test the prediction that morphologically similar species overlap in ecology. Both species are fruit and flower specialists, forage for patchily distributed food, fly with a foetus or young, and transport large-seeded fruits. Patterns of major foraging activity and foraging mode vary between species: P. samoensis is predominantly diurnal and uses soaring flight for commuting and assessing food resources, while P. tonganus is predominantly nocturnal and commutes extensive distances between roosts and foraging areas. Our results indicate that P. tonganus and P. samoensis are morphologically and ecologically similar, despite differences in flight behaviour. Differences in flight behaviour are attributable to the time of day when most extensive flying occurs for each species.

Relationships between Fruiting Seasons and Seed Dispersal Methods in a Neotropical Forest

The weight of fruits and seeds that fell into 75 polyethylene sheets, each 152 x 152 cm, totalling 175 m2 in area, was measured over a period of 17 months in the humid forest of Barro Colorado Island, in the Panama Canal Zone. A total of 72 species of fruits and seeds fell into the traps, and the number falling into any individual trap varied from three to 14. The number of fruiting species per month varied from 11 to 26, while the combined weight of fruits and seeds varied from a monthly average of 0.61-1.930 gm/square meter per day. Small-seeded fruits ripened rather evenly throughout the year, whereas large-seeded fruits tended to be seasonal. Although the primary determinants of fruiting times may be physical, small fruits the seeds of which pass unharmed through the guts of animals tend to be nonseasonal and thus avoid competition for dispersal. Fruits with large seeds that are destroyed by the animals eating them fruit synchronously. The agouti (Dasyprocta punctata), being unable to devour the entir...