The fig and pollinator wasp obligate mutualism is diverse (~750 described species), ecologically ... more The fig and pollinator wasp obligate mutualism is diverse (~750 described species), ecologically important, and ancient (~80-90 Ma), providing model systems for generating and testing many questions in evolution and ecology. Once thought to be a prime example of strict one-to-one cospeciation, current thinking suggests that genera of pollinator wasps coevolve with corresponding subsections of figs, but the degree to which cospeciation or other processes contributes to the association at finer scales is unclear. Here we use genome-wide sequence data from a community of Panamanian strangler figs (Ficus subgenus Urostigma, section Americana) and associated fig wasp pollinators (Pegoscapus spp.) to infer the process of coevolutionary diversification in this obligate mutualism. Using a model-based approach adapted from the study of gene family evolution, our results indicate pervasive and ongoing host switching of pollinator wasps at this fine phylogenetic and regional scale. Although th...
SUMMARYThe natural history of fig-pollinating wasps and their associated species-specific nematod... more SUMMARYThe natural history of fig-pollinating wasps and their associated species-specific nematodes allows the measurement of many parameters which are relevant to testing hypotheses concerning host-parasite ecology and evolution. Within fig wasps species, it is possible to estimate lifetime reproductive success of foundress wasps as a function of presence or absence of nematode parasitism (virulence). Across species, there is a wide range of host population structures which, in turn, results in a range of opportunities for either horizontal or vertical nematode transmission. Therefore, estimates of virulence can be related to opportunities for transmission across a group of closely related hosts and their parasites. Further, the dynamics of the nematode infections over ecological and short-term evolutionary timescales can be monitored, giving added insight into the interpretation of the virulence estimates. Moreover, several scales of longer term evolutionary relationships are eith...
Abstract For 18 species of Panamanian Ficus, representing both basal (Pharmacosycea; 4 spp.) and ... more Abstract For 18 species of Panamanian Ficus, representing both basal (Pharmacosycea; 4 spp.) and derived (Urostigma, Americana; 14 spp.) sections, we sampled multiple individuals per species and analyzed sequence data from multiple (3) genetic markers (tpi, g3pdh, ...
Parasitodiplogaster species associated with Ficus maxima were surveyed at the Smithsonian Tropica... more Parasitodiplogaster species associated with Ficus maxima were surveyed at the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama. Phase B-D syconia were collected from different trees and dissected in distilled water. Because there were different nematode stomatal and male morphotypes observed in a single sycone, nematodes isolated from each fig were observed to determine general morphotype class and stored individually in DNA extraction buffer for accurate morpho/molecular pairing. Additional voucher nematodes were gently heat-treated and fixed in formalin and processed into permanent mounts in dehydrated glycerin for more rigorous morphological examination. The survey yielded two different Parasitodiplogaster species: P. maxinema and P. pharmaconema n. sp. Several morphological characters, e.g., two long and stick-like teeth in the metastegostom, and stomatal dimorphism (presence of eurystomatous form) which were not previously described, were observed in P. maxinema and are ascribed hereto this species. Parasitodiplogaster pharmaconema n. sp. is morphologically similar to P. maxinema and P. yoponema but can be distinguished from these species based upon stomatal morphology, spicule and gubernaculum morphology, and number and arrangement of male genital papillae.
Ticks are important vectors of emerging zoonotic diseases. While adults of many tick species para... more Ticks are important vectors of emerging zoonotic diseases. While adults of many tick species parasitize mammals, immature ticks are often found on wild birds. In the tropics, difficulties in species-level identification of immature ticks hinder studies of tick ecology and tick-borne disease transmission, including any potential role for birds. In Panama, we found immature ticks on 227 out of 3,498 birds representing 93 host species, about 1/8th of the entire Panamanian terrestrial avifauna. Tick parasitism rates did not vary with temperature or rainfall, but parasitism rates did vary with host ecological traits: non-migratory residents, forest dwelling birds, bark insectivores, terrestrial foragers and lowland species were most likely to be infested with ticks. Using a molecular library developed from adult ticks specifically for this study, we identified 130 immature ticks obtained from wild birds, corresponding to eleven tick species, indicating that a substantial portion of the P...
Syconia (enclosed infructescences) infested with host-specific species of Schistonchus (Aphelench... more Syconia (enclosed infructescences) infested with host-specific species of Schistonchus (Aphelenchoididae) were collected from six species of Ficus (Moraceae) native to Florida or Panama. They were sectioned and histologically examined to assess the effects of parasitism. Parasitism by Schistonchus spp. was associated with hypertrophied cells, tissue necrosis, and the presence of an exudate in all species. Occasional hypertrophy of the outer epidermal cells occurred on seed florets, wasp florets, and on the endothecial cells of male florets in F. aurea (subgenus Urostigma) from Florida. Aberrations of the inner mesocarp occurred under the hypertrophied cells on seed florets. In F. laevigata (subgenus Urostigma) from Florida, Schistonchus sp. infested immature male florets and was associated with hypertrophy of endothecial cells, epidermal cells of the anther filaments, and anthers. Schistonchus sp. also caused aberrations of the anther filament, anthers, and pollen. Ficus poponoei (s...
Mutualisms are of fundamental importance in all ecosystems but their very existence poses a serie... more Mutualisms are of fundamental importance in all ecosystems but their very existence poses a series of challenging evolutionary questions. Recently, the application of molecular analyses combined with theoretical advances have transformed our understanding of many specific systems, thereby contributing to the possibility of a more general understanding of the factors that influence mutualisms.
The fig and pollinator wasp obligate mutualism is diverse (~750 described species), ecologically ... more The fig and pollinator wasp obligate mutualism is diverse (~750 described species), ecologically important, and ancient (~80-90 Ma), providing model systems for generating and testing many questions in evolution and ecology. Once thought to be a prime example of strict one-to-one cospeciation, current thinking suggests that genera of pollinator wasps coevolve with corresponding subsections of figs, but the degree to which cospeciation or other processes contributes to the association at finer scales is unclear. Here we use genome-wide sequence data from a community of Panamanian strangler figs (Ficus subgenus Urostigma, section Americana) and associated fig wasp pollinators (Pegoscapus spp.) to infer the process of coevolutionary diversification in this obligate mutualism. Using a model-based approach adapted from the study of gene family evolution, our results indicate pervasive and ongoing host switching of pollinator wasps at this fine phylogenetic and regional scale. Although th...
SUMMARYThe natural history of fig-pollinating wasps and their associated species-specific nematod... more SUMMARYThe natural history of fig-pollinating wasps and their associated species-specific nematodes allows the measurement of many parameters which are relevant to testing hypotheses concerning host-parasite ecology and evolution. Within fig wasps species, it is possible to estimate lifetime reproductive success of foundress wasps as a function of presence or absence of nematode parasitism (virulence). Across species, there is a wide range of host population structures which, in turn, results in a range of opportunities for either horizontal or vertical nematode transmission. Therefore, estimates of virulence can be related to opportunities for transmission across a group of closely related hosts and their parasites. Further, the dynamics of the nematode infections over ecological and short-term evolutionary timescales can be monitored, giving added insight into the interpretation of the virulence estimates. Moreover, several scales of longer term evolutionary relationships are eith...
Abstract For 18 species of Panamanian Ficus, representing both basal (Pharmacosycea; 4 spp.) and ... more Abstract For 18 species of Panamanian Ficus, representing both basal (Pharmacosycea; 4 spp.) and derived (Urostigma, Americana; 14 spp.) sections, we sampled multiple individuals per species and analyzed sequence data from multiple (3) genetic markers (tpi, g3pdh, ...
Parasitodiplogaster species associated with Ficus maxima were surveyed at the Smithsonian Tropica... more Parasitodiplogaster species associated with Ficus maxima were surveyed at the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama. Phase B-D syconia were collected from different trees and dissected in distilled water. Because there were different nematode stomatal and male morphotypes observed in a single sycone, nematodes isolated from each fig were observed to determine general morphotype class and stored individually in DNA extraction buffer for accurate morpho/molecular pairing. Additional voucher nematodes were gently heat-treated and fixed in formalin and processed into permanent mounts in dehydrated glycerin for more rigorous morphological examination. The survey yielded two different Parasitodiplogaster species: P. maxinema and P. pharmaconema n. sp. Several morphological characters, e.g., two long and stick-like teeth in the metastegostom, and stomatal dimorphism (presence of eurystomatous form) which were not previously described, were observed in P. maxinema and are ascribed hereto this species. Parasitodiplogaster pharmaconema n. sp. is morphologically similar to P. maxinema and P. yoponema but can be distinguished from these species based upon stomatal morphology, spicule and gubernaculum morphology, and number and arrangement of male genital papillae.
Ticks are important vectors of emerging zoonotic diseases. While adults of many tick species para... more Ticks are important vectors of emerging zoonotic diseases. While adults of many tick species parasitize mammals, immature ticks are often found on wild birds. In the tropics, difficulties in species-level identification of immature ticks hinder studies of tick ecology and tick-borne disease transmission, including any potential role for birds. In Panama, we found immature ticks on 227 out of 3,498 birds representing 93 host species, about 1/8th of the entire Panamanian terrestrial avifauna. Tick parasitism rates did not vary with temperature or rainfall, but parasitism rates did vary with host ecological traits: non-migratory residents, forest dwelling birds, bark insectivores, terrestrial foragers and lowland species were most likely to be infested with ticks. Using a molecular library developed from adult ticks specifically for this study, we identified 130 immature ticks obtained from wild birds, corresponding to eleven tick species, indicating that a substantial portion of the P...
Syconia (enclosed infructescences) infested with host-specific species of Schistonchus (Aphelench... more Syconia (enclosed infructescences) infested with host-specific species of Schistonchus (Aphelenchoididae) were collected from six species of Ficus (Moraceae) native to Florida or Panama. They were sectioned and histologically examined to assess the effects of parasitism. Parasitism by Schistonchus spp. was associated with hypertrophied cells, tissue necrosis, and the presence of an exudate in all species. Occasional hypertrophy of the outer epidermal cells occurred on seed florets, wasp florets, and on the endothecial cells of male florets in F. aurea (subgenus Urostigma) from Florida. Aberrations of the inner mesocarp occurred under the hypertrophied cells on seed florets. In F. laevigata (subgenus Urostigma) from Florida, Schistonchus sp. infested immature male florets and was associated with hypertrophy of endothecial cells, epidermal cells of the anther filaments, and anthers. Schistonchus sp. also caused aberrations of the anther filament, anthers, and pollen. Ficus poponoei (s...
Mutualisms are of fundamental importance in all ecosystems but their very existence poses a serie... more Mutualisms are of fundamental importance in all ecosystems but their very existence poses a series of challenging evolutionary questions. Recently, the application of molecular analyses combined with theoretical advances have transformed our understanding of many specific systems, thereby contributing to the possibility of a more general understanding of the factors that influence mutualisms.
Uploads