Atrazine Exposure Affects the Ability of Crayfish (Orconectes rusticus) to Localize a Food Odor Source

Abstract

Environmental pollutants, found in aquatic ecosystems, have been shown to have an effect on olfactory-mediated behaviors including feeding, mate attraction, and other important social behaviors. Crayfish are polytrophic, meaning that they feed on and become prey for all levels of the aquatic food web as well as are also important for the transfer of energy between benthic and terrestrial food webs. Because crayfish are a keystone species, it is important to investigate any factors that may affect their population size. Crayfish are active at night and rely heavily on their sensory appendages (e.g., antennulues, maxillipeds, and pereopods) to localize food sources. In this experiment, we investigated the effects of atrazine (ATR) exposure on the chemosensory responses of male and female crayfish to food odors. We exposed crayfish to environmentally relevant, sublethal levels of ATR [80 ppb (µg/L)] for 72 h and then examined the behavioral responses of both ATR-treated and control crayfish to food odor delivered from one end of a test arena. We used Noldus Ethovision XT software to measure odor localization and locomotory behaviors of crayfish in response to food (fish) odor. We found that control crayfish spent more time in the proximal region of the test arena and at the odor source compared with ATR-treated crayfish. Furthermore, there were no differences in the time spent moving and not moving, total distance travelled in the tank, and walking speed (cm/s) when control and ATR-treated crayfish were compared. Overall, this indicates that acute ATR exposure alters chemosensory abilities of crayfish, whereas overall motor function remains unchanged.

Acute Atrazine Exposure has Lasting Effects on Chemosensory Responses to Food Odors in Crayfish (Orconectes virilis)

“…A noticeable decrease in electro-olfactogram (EOG) response to female priming pheromone (prostaglandin F 2a ) was evident in mature male Atlantic salmon and to a known food odor (L-histidine) in rainbow trout after exposure of their olfactory epithelium to ATR (Moore and Lower 2001;Tierney et al 2007Tierney et al , 2008. Additionally, Belanger et al (2015) showed that crayfish (Orconectes rusticus), exposed to an environmentally relevant concentration of ATR, demonstrated decreases in their abilities to locate a food odor source. Consequently, ATR has a tremendous effect on the environment, and it is most likely that similar effects also are occurring in other aquatic species.…”

“…They transfer energy within Klaine et al (1988) Midwest streams and rivers [100 1989[100 -1990[100 Thurman et al (1991 Surface water sampling in the Midwest 108 1989-1990Thurman et al (1992 Midwest streams [100 1989[100 -1998[100 Scribner et al (2000 Northern Missouri and Midwestern streams 136 1994-1995Lerch et al (1998 Lake Adapted from Belanger et al (2015) the benthic food web, feeding on and becoming prey for many different levels of the aquatic food web (Creed 1994;Dorn and Wojdak 2004;Momot 1995;Momot et al 1978). Additionally, they transfer energy between the aquatic and terrestrial food chains as they become prey items for terrestrial animals (Lodge et al 1994).…”

“…Because rainbow trout could recover chemosensory responses to food odors fairly quickly, we hypothesized that crayfish also should recover responses to food odors quickly following an acute ATR exposure. Furthermore, based on results of Belanger et al (2015), we expected that overall crayfish mobility would be unaffected immediately after ATR exposure and during the recovery period. Because crayfish are nocturnally active benthic organisms, they rely heavily on chemical information to localize ecologically important odors, such as food odors.…”

“…Following precipitation events, concentrations of ATR in Midwest rivers and streams can reach levels greater than 100 ppb (lg/L) for several days (Table 1). Because we previously showed that ATR exposure affects the ability of crayfish (O. rusticus) to localize a food odor source (Belanger et al 2015), we wanted to investigate (1) if another species of crayfish (O. virilis) experienced the same chemosensory deficits post-ATR exposure, and (2) if crayfish could recover their chemoreceptive abilities 0, 24, 48, and 72 h following ATR exposure. Examination of chemosensory responses and recovery from ATR exposure was tested using a Y-maze.…”

“…While the 96-h LC 50 was determined to be 12.1 mg/L (Velisek et al 2013), much smaller, environmentally relevant concentrations (e.g. 80 ppb) have been shown to cause deleterious effects on the chemosensory abilities of crayfish (O. rusticus) in response to food odor (Belanger et al 2015). ATR ranges from slight to highly toxic to freshwater invertebrates (ranging between 60 and 250 ppb) with reductions in invertebrate numbers occurring between 62 and 92 ppb (EPA 2003).…”