The Branched and Isoprenoid Tetraether (BIT) index (a ratio of marine and terrestrial glycerol dialkyl glycerol tetraether [GDGT] membrane lipids) was recently introduced as a proxy for the fraction of fluvially derived organic carbon (OC) buried in marine sediments. We investigate the source and distribution of terrestrial OC in marine sediments in a large spatial data set that encompasses the Washington-Vancouver Island Margin, Vancouver Island fjords, and Puget Sound with the goal of comparing the BIT index to other traditional measures of terrestrial OC (d 13 C of OC [d 13 C org ] and lignin phenols). d 13 C org values and lignin concentrations indicate that the fjords are a significant trap for undegraded, wood-derived terrestrial material, with surface sediments containing up to 76% terrestrial OC. These proxies also show significant terrestrial OC contributions to margin sediments (up to 54%), with most likely an angiosperm source from the Columbia River. In contrast to d 13 C org values and lignin concentrations, BIT index values indicate extremely low terrestrial carbon throughout the study area (BIT index values range from 0 to 0.28) and are uncorrelated with the other proxies. Though the BIT index did not correlate with other proxies, margin GDGT concentrations varied offshore similarly to other terrestrially derived OC and are well-correlated with other proxies. We suggest that the BIT index is best interpreted as a proxy for soil-or peat-derived OC. The majority of terrestrially derived OC delivered to sediment in this area has a lignin-rich, nonsoil source. The disparity between the BIT index and other proxies implies that the BIT index significantly underestimates terrestrial relative to marine OC input to sediments in areas in which riverine OC input is not soil or peat derived.

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Widespread use of agrochemicals in the U.S. has led to nearly universal contamination of beeswax in honey bee hives. The most commonly found agrochemicals in wax include beekeeper-applied miticides containing tau-fluvalinate, coumaphos, or amitraz, and field-applied pesticides containing chlorothalonil or chlorpyrifos. Wax contaminated with these pesticides negatively affects the reproductive quality of queens and drones. However, the synergistic effects of these pesticides on the growth and survival of incipient colonies remain understudied. We established new colonies using frames with wax foundation that was pesticide free or contaminated with field-relevant concentrations of amitraz alone, a combination of tau-fluvalinate and coumaphos, or a combination of chlorothalonil and chlorpyrifos. Colony growth was assessed by estimating comb and brood production, food storage, and adult bee population during a colony’s first season. We also measured colony overwintering survival. We found no significant differences in colony growth or survivorship between colonies established on pesticide-free vs. pesticide-laden wax foundation. However, colonies that had Varroa destructor levels above 3% in the fall were more likely to die over winter than those with levels below this threshold, indicating that high Varroa infestation in the fall played a more important role than initial pesticide exposure of wax foundation in the winter survival of newly established colonies.

Information regarding black soldier fly (Diptera: Stratiomyidae) adult biology is vital as this is the life stage that produces eggs and thus drives population size. The goal of this study was to determine key biological characteristics of adult black soldier flies as they age in relation to: (1) the thermal preferences (Tsel) of males and females; (2) the impact of temperature on heat shock protein expression in males and females; as well as (3) the sperm count; and (4) the sperm viability in males. Aging significantly impacted male and female temperature preferences. Young males (<24-h-old) preferred warmer temperatures (median=24.3 °C, range=19.3-28.2 °C) compared to females of the same age (median=20.2 °C, range=15.4-26.2 °C). However, in older adults (i.e. 72-h-old males and 48-h-old females), temperature preferences converged between 21 and 24 °C. Temperatures tested did not impact hsp expression in males or females. However, aging males, but not females, had increased expression of the heat shock proteins (hsp) hsp70 and hsp90. Furthermore, age impacted sperm count but not sperm viability in males. In particular, 48-h-old males had the greatest sperm count (322.5/sample) and sperm viability (60-78%) compared to all other aged males. Thermal data in conjunction with sperm data potentially explain why early thermal segregation behaviour between males and females occurs. Once adult males and females reached 72-h-old and 48-h-old, respectively, they exhibited a common thermal preference, which coincided with the greatest number of viable sperm in males. Forcing adults into environments (i.e. cages) outside these selected preferences could result in premature or delayed mating or low fertilisation rates. Future research exploring cage design and conditions are needed to optimise black soldier fly colony maintenance and fertile egg production, and can leverage information such as the results described here.

Recent work demonstrated that honey bee (Apis mellifera L.) queens reared in pesticide-laden beeswax exhibit significant changes in the composition of the chemicals produced by their mandibular glands including those that comprise queen mandibular pheromone, which is a critical signal used in mating as well as queen tending behavior. For the present study, we hypothesized that pesticide exposure during development would alter other queen-produced chemicals, including brood pheromone in immature queens, thus resulting in differential feeding of queen larvae by nurse workers, ultimately impacting adult queen morphology. We tested these hypotheses by rearing queens in beeswax containing field-relevant concentrations of (1) a combination of tau-fluvalinate and coumaphos, (2) amitraz, or (3) a combination of chlorothalonil and chlorpyrifos. These pesticides are ubiquitous in most commercial beekeeping operations in North America. We observed nurse feeding rates of queen larvae grafted into pesticide-laden beeswax, analyzed the chemical composition of larval queen pheromones and measured morphological markers in adult queens. Neither the nurse feeding rates, nor the chemical profiles of immature queen pheromones, differed significantly between queens reared in pesticide-laden wax compared to queens reared in pesticide-free wax. Moreover, pesticide exposure during development did not cause virgin or mated adult queens to exhibit differences in morphological markers (i.e., body weight, head width, or thorax width). These results were unexpected given our previous research and indicate that future work is needed to fully understand how pesticide exposure during development affects honey bee queen physiology, as well as how various adult queen quality metrics relate to each other.