Bedbugs evolved before their bat hosts and did not co-speciate with ancient humans

All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]

Effect of Sub-Lethal Exposure to Ultraviolet Radiation on the Escape Performance of Atlantic Cod Larvae (Gadus morhua)

The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to depletion of the ozone layer. Several studies have reported that UV radiation reduces survival of fish larvae. However, indirect and sub-lethal impacts of UV radiation on fish behavior have been given little consideration. We observed the escape performance of larval cod (24 dph, SL: 7.6±0.2 mm; 29 dph, SL: 8.2±0.3 mm) that had been exposed to sub-lethal levels of UV radiation vs. unexposed controls. Two predators were used (in separate experiments): two-spotted goby (Gobiusculus flavescens; a suction predator) and lion's mane jellyfish (Cyanea capillata; a “passive" ambush predator). Ten cod larvae were observed in the presence of a predator for 20 minutes using a digital video camera. Trials were replicated 4 times for goby and 5 times for jellyfish. Escape rate (total number of escapes/total number of attacks ×100), escape distance and the number of larvae remaining at the end of the experiment were measured. In the experiment with gobies, in the UV-treated larvae, both escape rate and escape distance (36%, 38±7.5 mm respectively) were significantly lower than those of control larvae (75%, 69±4.7 mm respectively). There was a significant difference in survival as well (UV: 35%, Control: 63%). No apparent escape response was observed, and survival rate was not significantly different, between treatments (UV: 66%, Control: 74%) in the experiment with jellyfish. We conclude that the effect and impact of exposure to sub-lethal levels of UV radiation on the escape performance of cod larvae depends on the type of predator. Our results also suggest that prediction of UV impacts on fish larvae based only on direct effects are underestimations

Further Observations on the Representation of the Visual Field in the Occipital Cortex Using Functional MRI

The current revised map of the representation of the field of vision in the occipital cortex is based on lesional parametric studies in humans. The correlation between visual field analysis and occipital cortical function is difficult because of considerable anatomical variations in the striate cortex between individuals

Post-fledging mortality: A survival bottleneck for prairie falcons?

Volume: 27Start Page: 77End Page: 7

Behavior of Prairie Falcons (\u3cem\u3eFalco mexicanus\u3c/em\u3e) During the Nesting and Fledging-Dependence Periods Under Fluctuating Prey Conditions

We studied the behavior of adult and young prairie falcons (Falco mexicanus) during the nesting and fledging-dependence periods over a period of years when the population density of their primary prey, Townsend\u27s ground squirrels (Spermophilus townsenii), dramatically declined. The percentage of time adult male falcons spent in their nesting territories during the early brood-rearing period was significantly higher in 1992, the year of greatest ground squirrel abundance, than in 1991, a moderately high prey year, or in 1993 and 1994, the low prey years. Mean prey delivery rates during the entire brood-rearing period were similar among all years, but rates increased as nestlings aged in 1992, whereas they decreased as nestlings agged in 1991, 1993, and 1994. Prent falcons delivered proportionally fewere ground squirrels and small mammals, but more birds and reptiles in 1993 and 1994 than in 1992. This increased use of alternative prey likely represents compensation for low ground squirrel abundance. The ages at which falcons dispersed from their natal territories were similar between 1992 and 1993. However, low ground squirrel abundance may explain why the length of the staging period (the time between dispersal from the natal territory and emigration from the study area) was significantly lower in 1992 than in 1993

Fledging and migration of juvenile bald eagles from Glacier National Park, Montana

Volume: 30Start Page: 79End Page: 8