stages have been reviewed separately, and the variability of the published
methodologies has been considered, in order to draw attention to the current
discrepancies in the literature.
2 Acclimation Conditions
The first stage of an experiment (both in situ and ex situ) is the acclimation period
that should be used to acclimate the organisms to the experimental conditions.
However, the acclimation conditions are not always fully disclosed, and when
they are, they sometimes contradict the experimental conditions. The reproducibility
of an experiment is also highly dependent on many abiotic and biotic factors, which
are rarely taken into consideration for Gammarid feeding studies (Coulaud et al.
2011). In the following sections, different variables (duration, temperature, light/
dark cycles, type of water and organisms) that could impact the outcome of an
experiment have been reviewed separately and summarised in Table 1, in order to
emphasise the full range of variability within the literature. In some studies,
Gammarids are sourced from laboratory breeding programs (e.g. Blockwell et al.
1996; Bloor and Banks 2006a, b; McCahon and Pascoe 1988).
2.1 Duration
Acclimation periods vary depending on the study (see Table 1), for example, Agatz
et al. (2014) kept specimens of Gammarus pulex in the laboratory for 3 days prior to
the start of the experiment, whereas another study left Gammarus fossarum organisms to acclimate for 21 days (Garcia-Galan et al. 2017). Typically the acclimation
period used for Gammarids appears to be between 5 and 7 days, but some studies
have selected longer intervals up to 35 days (see Table 1). Agatz and Brown (2014)
stated that a 1-day acclimation period helped to reduce the variability of their results
by just 1.6%, suggesting that a longer acclimation period could potentially have an
even greater impact on reducing the intraspecific variability and consequently
strengthen the statistics. Although experimental controls are incorporated into the
majority of experimental designs, it becomes difficult to compare published peerreviewed research when the test organisms have experienced anything between
3 and 35 days acclimation to laboratory conditions (Agatz et al. 2014; GarciaGalan et al. 2017) (see Table 1), even more so when the organisms are used as
water quality biomonitors for in situ experiments (see Table 1).
Feeding Behavioural Studies with Freshwater Gammarus spp.: The. . .
3
methodologies has been considered, in order to draw attention to the current
discrepancies in the literature.
2 Acclimation Conditions
The first stage of an experiment (both in situ and ex situ) is the acclimation period
that should be used to acclimate the organisms to the experimental conditions.
However, the acclimation conditions are not always fully disclosed, and when
they are, they sometimes contradict the experimental conditions. The reproducibility
of an experiment is also highly dependent on many abiotic and biotic factors, which
are rarely taken into consideration for Gammarid feeding studies (Coulaud et al.
2011). In the following sections, different variables (duration, temperature, light/
dark cycles, type of water and organisms) that could impact the outcome of an
experiment have been reviewed separately and summarised in Table 1, in order to
emphasise the full range of variability within the literature. In some studies,
Gammarids are sourced from laboratory breeding programs (e.g. Blockwell et al.
1996; Bloor and Banks 2006a, b; McCahon and Pascoe 1988).
2.1 Duration
Acclimation periods vary depending on the study (see Table 1), for example, Agatz
et al. (2014) kept specimens of Gammarus pulex in the laboratory for 3 days prior to
the start of the experiment, whereas another study left Gammarus fossarum organisms to acclimate for 21 days (Garcia-Galan et al. 2017). Typically the acclimation
period used for Gammarids appears to be between 5 and 7 days, but some studies
have selected longer intervals up to 35 days (see Table 1). Agatz and Brown (2014)
stated that a 1-day acclimation period helped to reduce the variability of their results
by just 1.6%, suggesting that a longer acclimation period could potentially have an
even greater impact on reducing the intraspecific variability and consequently
strengthen the statistics. Although experimental controls are incorporated into the
majority of experimental designs, it becomes difficult to compare published peerreviewed research when the test organisms have experienced anything between
3 and 35 days acclimation to laboratory conditions (Agatz et al. 2014; GarciaGalan et al. 2017) (see Table 1), even more so when the organisms are used as
water quality biomonitors for in situ experiments (see Table 1).
Feeding Behavioural Studies with Freshwater Gammarus spp.: The. . .
3