Effects of Oil on Cricket Survival in Barataria Marshes

We monitored cricket colonies to determine the effect of oil on cricket survival rates. The objective was to determine if direct and indirect contact with weathered oil emulsions associated with the DWH oil spill caused increased mortality in the house cricket, Acheta domesticus Linnaeus (Orthoptera: Gryllidae) in the lab. The mortality of A. domesticus, in in situ bioassays is being used to indicate the presence of airborne oil, airborne oil constituents, possible airborne metabolites, and chemical constituents from ultraviolet breakdown or solar insoluation in the salt marshes of south Louisiana since the DWH spill (unpublished results). We investigated the cause of mortality in laboratory trials. We conducted experiments looking at both direct and indirect exposure to the oil emulsion under constant environmental conditions. The hypotheses tested were: Direct contact with weathered oil from the DWH spill will increase mortality in Achet a domesticus; and Indirect contact with weather oil from the DWH spill through exposure to only vapors will increase mortality in Acheta domesticus. The time for 50% and 100% mortality to occur in A. domesticus was significantly less when exposed to direct contact with oil (p < 0.0001 for both 50% and 100%) and indirect contact with oil (p = 0.0053, p = 0.0005 for 50% and 100%, respectively). House crickets exposed to oil vapors showed reduced adult life spans, longer time to maturation, and changes in resistance to parasites when compared with controls.

本研究通过监测蟋蟀种群，旨在明确石油对蟋蟀存活率的影响。本研究的核心目标为：在实验室环境下，探究与DWH漏油事件（Deepwater Horizon oil spill）相关的风化石油乳液的直接与间接接触，是否会导致家蟋蟀（Acheta domesticus Linnaeus，直翅目（Orthoptera）蟋蟀科（Gryllidae））的死亡率升高。自DWH漏油事件以来，针对家蟋蟀的原位生物测定（in situ bioassays）所测得的死亡率，被用于指示南路易斯安那州盐沼中空气传播石油、空气传播石油组分、潜在空气传播代谢物，以及紫外线降解或日晒产生的化学组分的存在（未发表数据）。本研究在实验室试验中探究了该致死现象的成因，在恒定环境条件下开展了针对石油乳液直接暴露与间接暴露的相关实验。本研究检验了两项假说：其一，接触DWH漏油事件产生的风化石油会升高家蟋蟀的死亡率；其二，仅通过蒸汽暴露的间接接触DWH漏油事件产生的风化石油，同样会升高家蟋蟀的死亡率。家蟋蟀达到50%和100%死亡率的时间，在直接接触石油组中显著缩短（50%和100%死亡率对应的p值均＜0.0001），在间接接触石油组中同样显著缩短（50%死亡率对应的p值为0.0053，100%死亡率对应的p值为0.0005）。相较于对照组，暴露于石油蒸汽的家蟋蟀成虫寿命缩短、成熟所需时间延长，且寄生虫抗性发生改变。