Parasite diversity of Nyctiphanes simplex and Nematoscelis difficilis (Crustacea: Euphausiacea) along the northwestern coast of Mexico

Abstract

The diversity of parasites found on Nyctiphanes simplex and Nematoscelis difficilis (Order Euphausiacea) was compared during 10 oceanographic cruises made off both coasts of the Baja California peninsula, Mexico. We tested the hypothesis that N. simplex has a more diverse parasitic assemblage than N. difficilis because it is a neritic species, has larger population abundance, and tends to form denser and more compact swarms than N. difficilis. These biological and behavioral features may enhance parasite transmission within swarms. We detected 6 types of ectoparasites: (1) epibiotic diatoms Licmophora sp.; (2) Ephelotidae suctorian ciliates; (3) Foettingeriidae exuviotrophic apostome ciliates; (4) an unidentified epicaridean cryptoniscus larvae (isopoda); and 2 castrators: (5) the ectoparasitic Dajidae isopod Notophryxus lateralis and (6) the ellobiopsid mesoparasite Thalassomyces fagei. We also detected 7 types of endoparasites: (1) an undescribed Collinia ciliate (Apostomatida); 3 types of Cestoda: (2) a Tetrarhynchobothruium sp. (Trypanorhyncha), (3) Echinobothrium sp. (Diphyllidea: Echinobothyriidae), and (4) unidentified metacestode; (5) a Trematoda Paronatrema-like metacercaria (Syncoeliidae); (6) the nematode Anisakis simplex (L3); and (7) Polymorphidae acantocephalan larvae (acanthor, acanthella, and cystacanth larval stages). N. simplex is affected by all types of parasites, except the isopod N. lateralis, having a considerably larger parasitic diversity and prevalence rates than N. difficilis, which is only infested with 3 types of ectoparasites and T. fagei. Euphausiid swarming is an adaptive behavior for reproduction, protection against predators, and increased efficiency in food searching, but has a negative effect due to parasitism. Although the advantages of aggregation must overcome the reduction of population and individual fitness induced by parasites, we demonstrated that all types of parasites can affect ~14% of N. simplex individuals. Collinia spp. endoparasitoids must occasionally have a significant influence on population mortality with potential epizootic events.KEY WORDS: Parasites · Parasitoids · Euphausiids · Nyctiphanes simplex · Nematoscelis difficilis · Bahía Magdalena · Gulf of California Resale or republication not permitted without written consent of the publisherDis Aquat Org 88: [249][250][251][252][253][254][255][256][257][258][259][260][261][262][263][264][265][266] 2010 increasing number of parasites and parasitoids have been discovered. The parasites of euphausiids include an array of interspecific associations that ranges from almost innocuous parenthetic epibiotic organisms such as diatoms (McClatchie et al. 1990), suctorians (Nicol 1984, Tarling & Cuzin-Roudy 2008, and apostome exuviotrophic ciliates (Lindley 1978, Rakusa-Suszczewski & Filcek 1988, Landers et al. 2006, to castrators (Field 1969) and parasitoids (Capriulo & Small 1986, Gómez-Gutiérrez et al. 2003, 2006, 2009. It is now apparent that each euphausiid species has a complex interspecific parasite...

Pseudocollinia brintoni gen. nov., sp. nov. (Apostomatida: Colliniidae), a parasitoid ciliate infecting the euphausiid Nyctiphanes simplex

“…During a study of the fecundity and molting rates of N. simplex carried out along the southwest coast of the Baja California peninsula and Gulf of California, Mexico, Gómez-Gutiérrez et al (2010b,c) discovered several adults infected with a novel apostome species similar to those previously assigned to the genus Collinia (Capriulo & Small 1986, Capriulo et al 1991, Gómez-Gutiérrez et al 2003, 2010a. Here, we formally establish the new genus Pseudocollinia gen. nov. and describe its type species as Pseudocollinia brintoni sp.…”

“…Local zooplanktonic female decapods and mysids undergoing similar experiments with filaments were not affected, suggesting highly specific infection with euphausiids. So far, no other euphausiid species from either coast of the Baja peninsula have been observed infected with Pseudocollinia (Gómez-Gutiérrez et al 2010a). …”

“…Parasites regularly cause a gradient of damage to their hosts, ranging from almost innocuous to lethal effects (Bradbury 1994, Morado & Small 1995, Gómez-Gutiérrez et al 2003, 2009, 2010a. Parasitoids are categorized as lethal when they must kill their host to complete their life cycle, with an ecological function analogous to predators (Lafferty & Kuris 2002).…”

Histophagous ciliate Pseudocollinia brintoni and bacterial assemblage interaction with krill Nyctiphanes simplex. II. Host responses

“…Total lipid and total polyunsaturated fatty acid content were analyzed in krill from Bahía Magdalena collected in December 2004 and from the Gulf of California in November 2005 and January 2007. Hydroacoustic detection and field sampling methods for krill are described in detail elsewhere (Gómez-Gutiérrez & Robinson 2006, Gómez-Gutiérrez et al 2010a,b, 2012a,b, Tremblay et al 2010.…”

“…Other protists, such as apostome ciliates of the genus Pseudocollinia, can cause epizootic events of adult krill populations (Gómez-Gutiérrez et al 2003). Research on histophagous ciliates infecting krill has mostly focused on taxonomic perspectives and biology (Capriulo & Small 1986, Capriulo et al 1991, Stankovic & RakusaSuszczewski 1996, Gómez-Gutiérrez et al 2003, 2010a, 2012a, Lynn et al 2014. Considerably less is known about aspects of Pseudocollinia ecology, parasite−host interactions, and physiological and biochemical composition between healthy and Pseudocollinia-infected krill.…”