Aedes albopictus, a species known to transmit dengue and chikungunya viruses, is primarily a container-inhabiting mosquito. The potential for pathogen transmission by Ae. albopictus has increased our need to understand its ecology and population dynamics. Two parameters that we know little about are the impact of direct density-dependence and delayed density-dependence in the larval stage. The present study uses a manipulative experimental design, under field conditions, to understand the impact of delayed density dependence in a natural population of Ae. albopictus in Raleigh, North Carolina. Twenty liter buckets, divided in half prior to experimentation, placed in the field accumulated rainwater and detritus, providing oviposition and larval production sites for natural populations of Ae. albopictus. Two treatments, a larvae present and larvae absent treatment, were produced in each bucket. After five weeks all larvae were removed from both treatments and the buckets were covered with fine mesh cloth. Equal numbers of first instars were added to both treatments in every bucket. Pupae were collected daily and adults were frozen as they emerged. We found a significant impact of delayed density-dependence on larval survival, development time and adult body size in containers with high larval densities. Our results indicate that delayed density-dependence will have negative impacts on the mosquito population when larval densities are high enough to deplete accessible nutrients faster than the rate of natural food accumulation.

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Striped Bass Morone saxatilis fisheries have been important in the eastern United States since the 1700s, but many populations have declined from historic levels. Enhancement programs, harvest reduction, water quality improvements, and habitat restoration have led to successful recoveries for specific stocks. However, these efforts have not been successful for the Striped Bass population in the Neuse River of North Carolina. Possible mechanisms inhibiting recovery of this population include overharvest, high discard mortality, poor water quality, and altered flow regimes. These mechanisms and their impacts on the Neuse River population are unclear; therefore, to gain insight, we estimated mortality and distribution of the population. Specifically, we tagged 100 hatchery-reared phase II juveniles (202-227 mm TL) and 111 resident adults (349-923 mm TL) with acoustic transmitters (a subset of 50 adults was also tagged with external high-reward tags). We used telemetry to monitor movement and seasonal distribution from December 2013 until September 2015. Telemetry and tag reporting data informed mortality models, and we estimated that annual discrete total mortality of phase II stocked juveniles was 66.3% (95% credible interval [CI] = 47.4-82.4%). Annual discrete total mortality of adults was 54.0% (95% CI = 41.5-65.4%). Adult discrete natural mortality was 20.1% (95% CI = 8.7-39.1%), and neither juvenile nor adult natural mortality was correlated with seasonal variation in dissolved oxygen, temperature, or salinity. These results show that poststocking mortality is significant and that juvenile mortality should be considered when establishing stocking goals. Additionally, adult natural mortality is within the range predicted by maximum age and by previous studies; however, adult total mortality is higher than targeted rates. These results can help to inform management decisions and develop measures to rebuild depressed Striped Bass populations like that in the Neuse River.

Divergence in vocalizations can reduce gene flow by serving as a premating barrier during secondary contact between previously isolated populations. In primates, vocal divergence in long calls of separated populations has been documented, yet recognition of these differences by the respective populations has seldom been studied in the field. To investigate this issue, we studied populations of two subspecies of saddle-back tamarins (Saguinus fuscicollis nigrifrons and S. f. lagonotus) that are separated by the Amazon River in Peru. We recorded long calls of each subspecies and detected significant differences between the populations in the number of notes per call, duration of calls, and shifts in starting frequency of notes over the length of calls. In addition, a population of S. f. nigrifrons responded more overtly in measures of approach to playback of long calls of its own subspecies compared to long calls of S. f. lagonotus. These results are consistent with the hypothesis that allopatric divergence of long calls might contribute to reproductive isolation of these subspecies of saddle-back tamarins, which adds to growing evidence suggesting full species status for these taxa.