Asplanchna and the spines of Brachionus calydflorus in two Javanese sewage ponds

Abstract

The lorica of the rotifer Brachionus calydflorus Pallas is variable in form. The most striking aspect of this variation is the presence or absence of posterolateral spines. Beauchamp (1952a,b), and, in more detail, Gilbert (1967), have shown that the presence of postero-lateral spines can be related to the presence of carnivorous rotifers ofthe genus Asplanchna. A substance liberated by Asplanchna causes females of Brachionus calydflorus to produce offspring with postero-lateral spines. Gilbert & Waage (1967) studied a natural population of 5. calydflorus and found that the length of the postero-lateral spines varied directly with the abundance of Asplanchna brightwelli Gosse. The greatest mean spine length that they found was 93-7 /xm when the density of Asplanchna was seventeen per litre. In Gilbert's (1967) laboratory experiments he recorded some individuals with postero-lateral spines up to 126 ^m in length.In plankton samples from two sewage ponds near Bandung in Java the posterolateral spines of B. calydflorus were extraordinarily long (Plate I). Measurements of 100 individuals from each pond are shown in Table 1. The samples had been taken quantitatively by filtering a known volume of water, so that we were able to estimate the density of the population and the density of Asplanchna brightwelli.The Javanese sewage ponds are extremely rich in zooplankton, and the density of Table 1. Population density of Asptanchna bn'ghtweltt and dimensions of Braehionus ealyciflorus in two sewage ponds No. Brachionus ealyeiflorus per litre No. Asplanchna brightwelli per litre Mean length of lonca of B. catyeiftortis Mean length of postero-lateral spines Mean length of postero-median spines Mean length of occipital spines Correspondence: Professor J. Green,

A review of potential methods for zooplankton control in wastewater treatment High Rate Algal Ponds and algal production raceways

“…At higher prey densities A. brightwelli increased their ingestion rate; at 25°C a single B. calyciflorus was ingested in~9-23 s, while the smaller A. fissa was ingested in just~3-4 s [286]. A. brightwelli has been reported in sewage ponds [287], and other species such as Asplanchna sieboldi had optimal growth in raw WW [73]; hence, they are potentially suited to the HRAP environment. If established in HRAPs, Asplanchna spp.…”

Effect of starvation time on the prey capture behaviour, functional response and population growth of Asplanchna sieboldi (Rotifera)

“…Being a planktonic predator, Asplanchna prefers slow moving and defenceless prey which, in most water bodies, are represented by members of Brachionidae (Ejsmont-Karabin, 1974;Green & Lan, 1974;Conde-Porcuna & Sarma, 1995). Being a planktonic predator, Asplanchna prefers slow moving and defenceless prey which, in most water bodies, are represented by members of Brachionidae (Ejsmont-Karabin, 1974;Green & Lan, 1974;Conde-Porcuna & Sarma, 1995).…”

Morphological and Morphometrical Variations of Selected Rotifer Species in Response to Predation: a Seasonal Study of Selected Brachionid Species from Lake Xochimilco (Mexico)

“…Gilbert (1999) has reviewed the role of asplanchnin produced by Asplanchna, which induces elongation of lorica spines in some members of Brachionidae. In nature too, it has been observed that many brachionids develop long spines if Asplanchna densities are high (Green & Lan, 1974). Studies on the feeding preferences of Asplanchna have shown that this predator indeed avoids prey types with defenses such as spines (Brachionus calyciflorus), setae (Filinia longiseta) and a darting movement (e.g., Hexarthra and Polyarthra) (Iyer & Rao, 1996).…”