Description of a new phytoseiid mite species ( Acari : Phytoseiidae ) from Egypt with a special reference to its biology

The adult female and male of the phytoesiid mite, Euseius plumerii Abo-Shanf & Romeih sp. n. were collected from leaves of both White Frangipani (Plumeria alba) and Rose (Rosa hybrida cv. Huddly) at Giza Governorate, Egypt, then identified and described. Furthermore, the description of immature stages was also presented. The life history of this new species were documented on the two spottedspider mite , Tetranychus urticae Koch movable stages which infested leaves of rose at three temperature degrees (20, 25 and 30±2 oC) and relative humidity of 70±5%. The results proved that, 30oC was the most suitable temperature degree which accelerated the life cycle, gave highly egg production and greatly prey consumption.


MATERIALS AND METHODS
The following species were found on leaves of both White Frangipani shrubs (Plumeria alba) at Faculty of Agriculture, Cairo University, Giza, Egypt, and rose (R. hybrida cv.Huddly) at Orman botanical garden, Giza.Samples were taken to the laboratory to extract the mites.Collected mite individuals were cleared in Nessbit's solution for a few minutes and mounted in Hoyer's medium on microscope slides for identification.All of the mounted mites were identified to species level under a light microscope using appropriate taxonomic references.They were then drawing by drawing eyepiece.Setal nomenclature followed in this manuscript is given in accordance with Rowell et al. (1978) and Chant & Hansell (1971) for dorsal and ventral surfaces, respectively.Dorsal and ventral idiosomal setal patterns are determined according to Chant andYoshida-Shaul (1989, 1991).All measurements were given in micron unit (µ).
The culture of E. plumerii sp.n. was started with a gravid female collected from leaves of White Frangipani shrubs.The mites were reared on a freshly Beefsteak leaf (Acalypha wilkesiana) placed upside down on moisten cotton pad in plastic tray.Water was added when needed maintaining suitable moisture.An abundance of T. urticae was offered daily to the predator as a main source of food, then maintained at 30±2ºC and 70±5% RH.Newly deposited eggs of the predator were transferred singly to Experimental Units (EU) each consisted of leaf disk (3cm diameter), manufactured from White Frangipani leaves floating on water-soaked cotton bed (diameter 10cm and 1cm thick) placed lower side upon a Petri dish (12cm diameter).The leaves' borders were surrounded by Tangle-foot to confine the mite and prevent it from escaping.The cotton was saturated with water daily during the test period.A known number of prey immature stages were offered to the predator newly hatched larvae as a food.Observations were made twice daily.Records were made daily on the duration of developmental stages, the number of prey consumed and the number of laid eggs at each EU.The observations continued until the end of longevity period.The entire tests were run at different temperatures: 20, 25 and 30 ±2°C.A total of 25 replicates per temperature degree were prepared.
Data were subjected to statically analysis by the aid of One Way ANOVA (F-test) with the computer programme (SAS Institute, 1988) which runs under WIN.The difference between means was determined by the help of Duncan's multiple range tests (Duncan, 1955) in this programme.

Euseius plumerii Abo-Shanf & Romeih sp. n. Diagnosis:
The new species E. plumerii is similarly well with E. scutalis (Athias-Henriot), but it differs in the shape and length of spermatheca; addition to the fixed digit is bidentate while those of E. scutalis is unidentate.Furthermore, the new species possesses macrosetae only on genu, tibia and basitarsus IV, but it presented on genu I-IV, tibia and tarsus IV in E. scutalis.
Type material: Holotype female was collected from leaves of White Frangipani shrubs at Faculty of Agriculture, Cairo University, Giza, Egypt, on February 18, 2006.Paratypes, several adult females collected from rose leaves in Orman botanical garden, Giza Governorate in 2006.Allotypes, several adult males collected with same data.
Etymology: plumerii, in homage to the plant species, which the type specimens collected from.

Biological studies
The female and male egg's incubation period increased with the decline in temperature degrees.Large effects of temperature degrees were recorded, whereas the longest life cycle averaged 12 & 10.54 days for both female and male; respectively was obtained at 20ºC, compared with those reared at 30ºC averaged 6.43 & 5.3 days (Table 1).Mating was essential for reproduction and multiple mating was important to complete reproduction, where it takes place after final moult (Hoy and Smilanick, 1979).Mating usually takes several hours (5-7 h) during the first copulation, while it decreases gradually during other ones.The male can mate more than one female and the latter accepted more than once.When the temperature slightly changed from 20 to 30ºC, the oviposition period decreased from 17.29 to 9.43 days (Table 2).The highest mean number of eggs (55.14/female) with the highest daily oviposition rate (5.85 eggs/day) was observed at 30ºC, the lowest daily oviposition rate (2.79 eggs/day) was obtained at 20ºC with a total of 48.29 eggs/female (Fig. 20).Larvae of some species of genus Euseius had been reported feed (Takafuji &Chant, 1976 andMomen, 1995).The larva of female and male of this species sucked (4 & 3), (6.86 & 5.75) and (7.29 & 6.25) immatures of T. urticae at 20, 25 and 30ºC, respectively (Table 3).Adult female and male of the predatory mite, E. plumerii sp.n. consumed the higest numbers of the prey at 30ºC (326.86 & 184.13 immatures) in caparisoning with those noticed at the others.
No agreeing with the findings of Kasap and Şekeroğlu (2004) who determined results with the biology and reproductive potential of E. scutalis using a diet of all life stages of the spider mite, Panonychus citri (McGregor), whereas the oviposition period was longer at 25°C than at 20 and 30°C, but the present result reported it prolonged at 20°C.

Table 1 :
Effect of temperature degrees on the duration of E. plumerii sp.n. different stages in days reared on T. urticae immatures infested rose leaves (R. hybrida cv.Huddly) at 70±5% RH Numbers in each column followed by different letters are significantly different (P= 0.05; Duncan's Multiple Range Test).

Table 2 :
Longevity and life span of E. plumerii sp.n. reared on T. urticae immatures infested rose leaves (R. hybrida cv.Huddly) at three temperature degrees and 70±5% RH Numbers in each column followed by different letters are significantly different (P= 0.05; Duncan's Multiple Range Test).

Table 3 :
Effect of temperature degrees on the consumption rate per day of E. plumerii sp.n. reared on T. urticae immatures infested rose leaves (R. hybrida cv.Huddly) at 70±5%RH Numbers in each column followed by different letters are significantly different (P= 0.05; Duncan's Multiple Range Test).