Depth and productivity as predictive parameters for the widespread invasion of Arctodiaptomus dorsalis (Marsh, 1907) (Copepoda: Calanoida) in tropical lakes in the Philippines

Abstract

A massive invasion of the Neotropical calanoid copepod Arctodiaptomus dorsalis (Marsh, 1907) has been taking place in the Philippines since at least 1993. This copepod’s fecundity is known to depend on food concentration, increasing temperature appears to have detrimental effects on its hatching success and survivorship, but parameters that are truly predictive of the successful integration and propagation of this species in particular bodies of water have not yet been identified. We conducted a spatial analysis of morphometric features and reproductive capacity, the latter proxied by clutch size (CS), of different populations of A. dorsalis inhabiting 11 tropical lakes in the Philippines. Correlations between either morphometry or CS and selected water quality parameters were investigated based on collections and measurements made from December 2018 to April 2019. Means of morphometric measurements differed significantly (P < 0.001) among the populations of A. dorsalis in all lakes. Total length (TL) of adult males, TL of non-ovigerous adult females, and CS of ovigerous females all showed significant (P < 0.001) inverse correlations with lake depth, accounting for about 30% of the observed variability among lakes (r = –0.55, –0.55, and –0.58, respectively). Shallow lakes, which are more homogenous in terms of nutrient distribution throughout the water column, thus provide a more suitable habitat than deep lakes for A. dorsalis and provides a partial explanation of the widespread occurrence and abundance of the species in the shallower, more eutrophic lakes in the Philippines.

Philippine Seven Tropical Maar Lakes are Ideal Habitats for the Invasive Arctodiaptomus dorsalis Marsh, 1907 (Copepoda: Calanoida)

“…As reported in previous studies, such conditions present the ideal environment for the propagation of the Invasive A. dorsalis, as it prefers and thrives in eutrophic waters (Elmore 1983;Tordesillas et al 2018;de Leon et al 2020).…”

“…According to Elmore (1983) and Tordesillas et al (2018), A. dorsalis can only survive in aquatic environments with high nutrient concentration, establishing its preference towards eutrophic waters. de Leon et al (2020) also reported that one of the largest, based on mean TL, and most fecund A. dorsalis was obtained from the same lake when they compared populations obtained from lakes located in South Luzon, Philippines. The second largest and most fecund ovigerous females, on the other hand, was obtained from Lake Sampaloc (mean PL = 0.87 mm; mean CS = 9.87 eggs female -1 ), the third shallowest lake among the sampling sites.…”

“…Papa et al (2012) reported that A. dorsalis was the only calanoid species in the SML. Recent studies have reaffirmed its presence leading to the assertion that it is already well established in the said lakes (Lopez et al 2017;de Leon et al 2020).…”

“…Experimental studies involving A. dorsalis have shown that its fecundity is directly associated with increasing food concentration (Elmore 1983;Tordesillas et al 2018), while an inverse relationship exists between its hatching success and survivorship with temperature (Tordesillas et al 2016). In situ investigations have also shown its preference towards shallow water bodies with high productivity (de Leon et al 2020). Utilizing this information, we assessed the effects of selected environmental factors on the established populations of A. dorsalis in the SML -seven highly utilized, proximal lakes with different physical characteristics.…”

Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers

“…In our study lakes, it has been reported that zooplankton communities are dominated by a calanoid copepod, A. dorsalis, which has become a common species in Philippine inland waters (Papa et al, 2012;De Leon et al, 2020). A. dorsalis is known as a selective phytoplankton grazer that prefers diatoms over cyanobacteria and green algae among phytoplankton assemblages (Cisneros et al, 1991).…”