Systematic & Applied Acarology 22(9): 1422–1430 (2017) http://doi.org/10.11158/saa.22.9.9
ISSN 1362-1971 (print) ISSN 2056-6069 (online)
Article
Life cycle of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) fed on Poultry Red Mite Dermanyssus gallinae (Acari: Dermanyssidae) MAICON TOLDI1, DAIÂNI CRISTINA CARDOSO FALEIRO1, GUILHERME LIBERATO DA SILVA1,2* & NOELI JUAREZ FERLA1,3 1
Laboratório de Acarologia, Tecnovates, UNIVATES – Universidade do Vale do Taquari. 95900-000 Lajeado, RS, Brasil. Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal do Rio Grande do Sul. 90050-170 Porto Alegre, RS, Brasil. 3 CNPq Researcher *Corresponding author, E-mail:
[email protected] 2
Abstract This study evaluated the biological characteristics of predatory mite Cheyletus malaccensis fed on Dermanyssus gallinae at different temperatures. The study started with thirty individual eggs of C. malaccensis each isolated in an experimental unit, which developed throughout their life stages while feeding on D. gallinae at each temperature tested (20ºC, 25ºC and 30±1ºC and 80±5% relative humidity). Emerged adult females were not mated, thus producing only male offspring (arrhenotoky). Fecundity was the highest at 25°C (415.62±24.78 eggs/female) and lowest at 20°C followed at 30ºC. The mean length of a generation did not displayed difference among the three temperatures, but the net reproductive rate (Ro), innate capacity for increase (rm) finite increase rate (λ) were significantly higher at 30°C and lower at 20°C. Cheyletus malaccensis was able to develop and reproduce successfully when fed D. gallinae, and the optimum temperature for development, fertility and survival was 25°C. Our findings proved that C. malaccensis might be a natural enemy of D. gallinae, because it was able to develop and reproduce while feeding exclusively on this ectoparasite. Keywords: Animal health; Ectoparasite; Poultry Red Mite (PRM); Predator
Introduction Under natural conditions birds develop defense strategies against mite infestations, such as using their nails, beak, and dust bathing. However, when reared in conventional cages for poultry their beak and nails may become deformed, making it difficult to remove mites, thereby requiring the use of ectoparasite control strategies (Tucci et al. 1998). With continuous use of pyrethroids, carbamates, and organophosphates, pest mites have become resistant. Additionally, the pesticides can have adverse effects on the bird´s nervous system, and can be immunosuppressive and carcinogenic (Zeman & Zelezny 1985; Fry 1995; Beugnet et al. 1997; Nordenfors et al. 2001). Furthermore, the use of synthetic acaricides is increasingly restricted by law and some products can leave residues in eggs, meat, liver, and animal adipose tissue (Fiddes et al. 2005). One of the most important ectoparasite of poultry and other bird species it is the poultry red mite Dermanyssus gallinae (De Geer), that it is a blood-feeding ectoparasite, representing one of the main economic health issues in commercial aviculture. It is responsible for anemia in birds, egg downgrading and spotting, and reports suggest it could be a vector for several human and animal diseases (Moro et al. 2009; De Luna et al. 2009). Throughout the day it shelters in wood crevices,
© Systematic & Applied Acarology Society
1422
feces, diverse dirt types, spider webs and visits its host only during night (Wood 1917; Zenner et al. 2009). The use of alternative control by means of natural predator practices is cleaner, causes less environmental impact (Guimarães et al. 2000; Lesna et al. 2009) and avoids the usage of chemical, reducing the use of toxic products by farmers (Guimarães et al. 2000). Non-chemical methods help mitigate environmental impacts caused by intensive production systems, reduce contamination of soil and water, and promote economic and social development (Sparagano et al. 2009). Mite control improves animal welfare (Lesna et al. 2009; Sparagano et al. 2009; Chirico & Tauson 2002), favors productive performance reduces vector-borne zoonotic diseases and provides a better working environment for farmers (Sparagano et al. 2009). Maurer & Hertzberg (2001) reported the spontaneous occurrence of Cheyletus eruditus (Schrank) (Cheyletidae) on aviaries from Switzerland, where they observed this predator feeding on immature stages of D. gallinae. However, the release of C. eruditus in aviaries did not result in effective control of those poultry red mites. Other predatory mite, Cheyletus malaccensis (Oudemans) is found in warehouses and barns (Hughes 1976) and often in bird and rodents nests, where it occurs in associated with mites belonging to the family Acaridae (Palyvos and Emmanouel 2011; Faleiro et al. 2015; Horn et al. 2016). This predator has arrhenotokous reproduction, in other words, virgin females produce males, while fertilized females generate offspring of both genders. Temperature affects its longevity, fecundity, survival, and efficiency in biological control (Palyvos and Emmanouel 2011; Pekár and Hubert 2008). Cheyletus malaccensis has been used in the biological control of mites in stored products (Lukás et al. 2007; Cebolla et al. 2009) and has been cited like a candidate predator for biological control of feather mite Megninia ginglymura (Mégnin) (Granich et al. 2016). However, there are no records of this species preying on D. gallinae. This work aimed to evaluate the life cycle of C. malaccensis feeding on D. gallinae at three different temperatures under laboratory conditions.
Material and Methods This study was conducted at the Laboratory of Acarology of the UNIVATES University Center and voucher specimens of C. malaccensis and D. gallinae were deposited in the mite reference collection of the Museu de Ciências Naturais of Centro Universitário UNIVATES (ZAUMCN), Lajeado, Rio Grande do Sul, Brazil. Stock colonies The colonies of C. malaccensis were obtained from cardboard traps in poultry houses, according to Lesna et al. (2009). Cheyletus malaccensis was kept in the laboratory feeding on D. gallinae obtained from the same poultry house where the predators were collected using cardboard traps (100 mm wide x 70 mm long x 3 mm high) placed on roosts, nests, columns and walls at laying hen system of free-range chicken (Cunha et al. 2009). Also, these traps were distributed near the upper vertex, sides and in front of the battery cages (Lesna et al. 2009). The individuals of C. malaccensis were fed on eggs and live immature stages of D. gallinae one month before start the study. Experimental units The experimental units consisted of a plastic plate (3 cm in diameter and 1.5 cm in height) covered with plastic film. The units were tested at three temperatures (20ºC, 25ºC and 30±1ºC) and 80±5% relative humidity. The predatory mites were tested before of start the experiment to verify if they are nutritionally adapted to diet used in the experiment and if the females can reproduce without males.
1423
SYSTEMATIC & APPLIED ACAROLOGY
VOL. 22
Biological parameters The study started with 30 eggs of C. malaccensis at each temperature, which were individualized and obtained from fertilized females from the stock colony. Females were removed after oviposition when laying a single egg in each unit. Post-embryonic stages of the predators were fed with a mixture of all prey stages considered as active forms. Immature stages of C. malaccensis were observed three times a day (08:00, 14:00 and 20:00 h). Events that occurred after 20:00 h were estimated to have occurred midway to the next observation, i.e. at 02:00 h. During the oviposition phase, a single observation was made daily, at 14:00 h in order to evaluate reproduction and survival. After the mites had reached adulthood, their sex was determined visually. The sex ratio was determined by counting the adult males and females originating from those eggs. Sex ratio is described as the proportion of females. Emerged adult females were not mated. The following parameters were evaluated: reproductive period (pre-oviposition, oviposition and post-oviposition), duration of developmental stages, oviposition rate (number of eggs/female/day), adult longevity (females and males), and sex ratio of the progeny. During the oviposition phase, the eggs were counted and removed from the experimental units. Data analysis For all tests, p values
