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2016-2017

3 hits

  • Thumbnail for Pollination Ecology and Natural History of  Pedicularis groenlandica
    Pollination Ecology and Natural History of Pedicularis groenlandica by Moffett, Zoe Starr

    Arctic and alpine ecosystems have been found to be highly susceptible to changes caused by shifts in global climate trends. For this reason, it is important to study both the plants and the pollinators within these vulnerable ecosystems in order to best hypothesize how their mutualistic relationships may be affected by predicted, future climates. My study focuses on exploring the natural history and reproductive strategies of Pedicularis groenlandica (little elephanthead or elephantella). P. groenlandica relies on an evolved behavior in its pollinators whereby they buzz-pollinate the flowers. This dependency on such a specific behavior makes P. groenlandica a particularly interesting alpine plant to study. Through various pollination treatments, I found that pollen may be limiting to the seedset of these flowers. Flowers that I hand-pollinated with extra pollen tended to have slightly heavier seeds than those which were naturally pollinated by bees alone. I used microphones to record the acoustics of bumblebee flight buzzes in order to see how the number of buzzes within a patch of flowers related to the seedset of those flowers. When controlled for factors of visibility (such as the number of inflorescences within the patch), the number of recorded buzzes predicted the average seed weight of the flowers within that patch. Combined with past studies on P. groenlandica, my findings indicate the importance of bumblebees, and their evolved buzz-pollination behaviors, to populations of this species.

  • Thumbnail for Spatial vision in band-winged grasshoppers (Orthoptera: Acrididae: Oedipodinae)
    Spatial vision in band-winged grasshoppers (Orthoptera: Acrididae: Oedipodinae) by Duncan, Alexander

    Visual acuity, the ability to resolve fine spatial details, can vary dramatically between and within insect species. Body-size, sex, behavior, and ecological niche are all factors that may influence an insect’s acuity. Band-winged grasshoppers (Oedipodinae) are a subfamily of grasshoppers characterized by their colorfully patterned hindwings. Although researchers have anecdotally suggested that this color pattern may attract mates, few studies have examined the visual acuity of these animals, and none have examined its implications on intraspecific signaling. Here, we compare the visual acuity of three bandwing species: Dissosteira carolina, Arphia pseudonietana, and Spharagemon equale. To measure acuity in these species we used a modified radius of curvature estimation (RCE) technique. Visual acuity was significantly coarser 1) in males compared to females, 2) parallel to the horizon compared to the perpendicular, and 3) in S. equale compared to other bandwings. Unlike many insect families, body size within a species did not correlate with visual acuity. To examine the functional implications of these results, we modeled the appearance of different bandwing patterns to conspecifics. These results suggest that hind- wing patterning could only be used as a signal to conspecifics at short distances (<50cm). This study furthers the exploration of behavior and the evolution of visual systems in bandwings.

  • Thumbnail for Spatial vision in band-winged grasshoppers (Orthoptera: Acrididae: Oedipodinae)
    Spatial vision in band-winged grasshoppers (Orthoptera: Acrididae: Oedipodinae) by Duncan, Alexander Brett

    Visual acuity, the ability to resolve fine spatial details, can vary dramatically between and within insect species. Body-size, sex, behavior, and ecological niche are all factors that may influence an insect’s acuity. Band-winged grasshoppers (Oedipodinae) are a subfamily of grasshoppers characterized by their colorfully patterned hindwings. Although researchers have anecdotally suggested that this color pattern may attract mates, few studies have examined the visual acuity of these animals, and none have examined its implications on intraspecific signaling. Here, we compare the visual acuity of three bandwing species: Dissosteira carolina, Arphia pseudonietana, and Spharagemon equale. To measure acuity in these species we used a modified radius of curvature estimation (RCE) technique. Visual acuity was significantly coarser 1) in males compared to females, 2) parallel to the horizon compared to the perpendicular, and 3) in S. equale compared to other bandwings. Unlike many insect families, body size within a species did not correlate with visual acuity. To examine the functional implications of these results, we modeled the appearance of different bandwing patterns to conspecifics. These results suggest that hind- wing patterning could only be used as a signal to conspecifics at short distances (<50cm). This study furthers the exploration of behavior and the evolution of visual systems in bandwings.