ENTOMOPHAGA, 27 (2), 1982, 135-139

I N F L U E N C E OF PREY SPECIES AND STAGES ON PREDATORY E F F I C I E N C Y

A N D D E V E L O P M E N T OF TWO P H Y T O S E I I D MITES

ALY H. RASMY (t), S.M. HAFEZ (2) & S.A. ELSAWY (3)

(1), (3) Plant Protection Dept., National Research Centre, Dokki, Cairo (2) Entomology Dept., Faculty of Agric., Ain-Shams Univ., Cairo, Egypt

The effect of prey species and the different stages of prey on the preda- tory efficiency and biology of the phytoseiid mites, Amblyseius gossipi ELBADRY and Typhlodromus mangiferus sp.n. was studied. It was found that feeding either predator on Tetranychus cucurbitacearum (SAYED) pro- moted faster development and a higher rate of oviposition than rearing on the twospotted spider mite, T.urticae (KOCH). Different stages of both prey species also produced different responses in the biological activities of these predaceous mitcs.

Mites of the family Phytoseiidae have received much attention because of their reproductive potential and ability to regulate phytophagous mite populations.

In Egypt, several studies have revealed that phytoseiids are widely distributed on different plantations and have a considerable role in biological control of acarine pests (ELBADRY & ELBANHAWY, 1968 ; ELBARDY et al., 1968 ; RASMY & ELBANHAWY, 1974 ; RASMY, 1977).

The present study has been conducted on the effect of different stages of prey as well as prey species, i.e. Tetranychus urticae (KOCH) and T.cucurbitacearum (SAVED) on the biological activities of 2 phytoseiid mites, Typhlodromus mangiferus sp.n. and Amblyseius gossipi ELBADRY. The afore mentioned phytophagous mites are the most common tetranychid mites infesting different crops in Egypt.

METHODS

Leaf discs of sweet potato, 6,5 cm 2 in area, were used as a substrate for rearing the phytoseiid mites. The leaf discs were kept in Petri dishes on water-saturated cotton. Newly hatched larvae of these mites were confined singly on the leaf discs.

In a 1st series of experiments, 3 groups of 20 larvae each, of the predatory mite T.mangiferus were reared on 3 different stages of T.urticae; eggs, larvae and nymphs.

136 ALY H. RASMY et aL

In a 2nd series of experiments, 2 groups of 20 larvae each, of T.mangiferus were fed on the eggs and nymphs of T.cucurbitacearum.

In a 3rd series of experiments, 3 groups of 20 larvae each, of A. gossipi were fed on the larvae and nymphs of T.urticae as well as nymphs of T.cucurbitacearum. A.gossipi refused to feed on eggs of either tetranychid species.

Larvae of T.cucurbitacearum were not used in either the 2nd or 3rd series of experiments because data obtained from the Ist series showed that duration of the immature stages as well as number of eggs deposited per predator 9 reared on T.urti- cae nymphs were similar to those of predators fed on prey larvae.

In all series of experiments, the development of predatory larvae up to adulthood was observed daily. Virgin predatory 9 were coupled with unmated o' within 24 h after the last moult. Eggs deposited per predatory 9 were recorded daily for 10 days after the pre-oviposition period.

The tetranychid immatures consumed were determined daily and replaced to maintain an ample food supply. Fresh leaf disc is with an ample supply of eggs of each tetranychid species were offered daily to T.magniferus reared on prey eggs. The experiments were conducted in the laboratory at a temperature of 25 ~ + 1 ~ C and about 70 o7o R.H.

RESULTS AND DISCUSSION

EFFECT OF PREY STAGES

Rearing T.manglferus on larvae and nymphs of T.urticae produced similar results and promoted faster development of the immature predators than when prey eggs were used for feeding. The rate of oviposition of the predatory 9 fed on prey nymphs or larvae was also higher than when prey eggs were used for rearing (table 1).

Similary when eggs and nymphs of T.cuc'urbitacearum were used for rearing T.mangiferus, the prey nymphs promoted faster development and a higher rate of ovi- position than did the prey eggs (table i).

Feeding A.gossipi on larvae or nymphs of T.urticae had a similar effect on its developmental period and oviposition rate (table 2).

EFFECT OF PREY SPECIES

Feeding the predatory mite, T.mangiferus on nymphs of T.cucurbitacearum pro- moted faster development and a higher rate of oviposition than when nymphs of T.urticae were used, but the eggs of both species of prey when fed to T.mangiferus had similar effect on its development and oviposition rate (table 1).

With A.gossipi, the developmental periods of the predator bred throughout on nymphs of either prey showed no obvious differences and its rate of oviposition when bred on T.cucurbitacearum nymphs appeared to be higher than that of 9 reared on T.urticae nymphs (table 2).

PREDATORY CONSUMPTION

It is evident from table 3 that both the immature and the adult stages of T.man- giferus consumed significantly higher numbers of eggs and nymphs of T.cucurbitacea- rum than those of T.urticae (P < 0.05 F-test). Concerning prey consumed by either sex of the predator, table 3 shows that 9 immatures of T.mangiferus fed on signifi- cantly higher numbers of eggs and larvae of T.urticae as well as eggs of T.cucurbita- cearum than immatures of the o" , while numbers of prey nymphs consumed by each sex were almost alike.

PREDATORY EFFICIENCY OF TWO PHYTOSEIIDS 137

TABLE 1

Developmental periods and numbers o f eggs laid per female o f T . m a n g i f e r u s as affected by feeding on different stages o f T . u r t i c a e and T . c u c u r b i t a c e a r u m

Average duration in days No. eggs

Larva Protonymph Deutonymph Total Preovip. in 10 days

T.urticae eggs

<~ 1.0 • 0 3.3 • 0.4 3,3 + 0.3 7,6 • 0.4 4.2 • 0.8 4.0 • 0,6 cr 1.0 • 0 3.9 • 0,3 2.5 • 0.3 7.4 • 0.4

T. urticae larvae

9 1.0 • 0 3.2 • 0,2 2.2 • 0.2 6.3 • 0.3 5.1 • 0.4 7.7 • 0.6 cr 1.0 +_ 0 2.6 + 0.2 2.4 + 0.3 6.0 • 0.4

T. urticae nymphs

9 1.0 • 0 3.1 • 0,3 2.6 • 0.2 6.7 + 0.2 3.7 • 0.2 8.3 • 0.4 cr 1.0 • 0 3.0 • 0.4 2.2 • 0.3 6.2 • 0.5

T.cucurbitacearum eggs

9 1.0 + 0 3,3 • 0.3 2,7 • 0.3 7.0 + 0.4 5.3 • 0.3 4.3 • 0.3 cY 1.0 + 0 2.8 + 0.4 3.4 +_ 0.4 7.2 • 0.6

T.cucurbitacearum nymphs

Q 1.0 • 0 2.3 • 0 1.7 • 0.2 5,0 • 0.2 3.1 • 0.2 13.3 • 1.6 cr 1.0 • 0 1.9 • 0.3 2.1 • 0.4 5.0 • 0.3

TABLE 3

Developmental periods and numbers o f eggs laid per female o f A . g o s s i p i as affected by feeding on larvae, nymphs o f T . u r t i c a e and nymphs o f T . c u c u r b i t a c e a r u m

Average duration in days No. eggs

Larva Protonymph Deutonymph Total Preovip. in 10 days

T. urticae larvae

9 1.4 + 0.2 1.8 • 0.1 1.6 • 0.1 4.8:1:0.2 2.8 + 0.1 14.4 + 1.0 c~ 1.3 + 0.2 1.7 • 0.2 1.1 • 0.2 4.1 • 0.2

T.urticae nymphs

9 1.4 • 0.1 1.7 • 0.2 1.3 + 0.2 4.4 • 0.3 2.6 • 0.4 15.1 + 1.0 o" 1.4 • 0.1 2.1 • 0.2 1.2 • 0.1 4.7 • 0.3

T.cucurbitacearum nymphs

9 1.4 • 0.1 1.8 • 0.2 1.3 + 0.2 4.5 :t: 0.2 2.3 + 0.2 17.3 • 0.8 1.3 • 0.1 2.2 • 0.3 1.0 • 0.0 4.5 • 0,2

138 A L Y H . R A S M Y et aL

TABLE 2

Average numbers o f immature stages o f T.urticae and T.cucurbitacearum consumed by different stages o f T.mangiferus

Dai ly a v e r a g e T o t a l

L a r v a P r o t o n y m p h D e u t o n y m p h A d u l t

T.urticae eggs

9 8 .2 ___ 0 .7 26 .8 + 1.8 33.8 + 3 .0 206 .5 + 7 .7 36.8 _+ 1.0 o" 6 .8 + 0 .6 21.3 _+ 2 .7 35 .9 + 2 .2 179.5 + 6.3 38.2 + 1.1

T.urticae l a r v a e

9 3 .8 + 0 .5 9 .0 + 0 .7 17.0 ___ 1.4 70 .0 + 2 .5 15.0 + 1.I o" 4 .0 + 0 .4 9 .9 + 0 .9 12.2 +_ 1.8 57.7 _+ 1.7 16.5 + 1.2

7". urticae n y m p h s

9 3 .0 + 0 .4 4 .2 + 0 .4 4 .6 + 0 .5 28 .0 + 2 .3 6 .6 +_ 0 .3 cr 3 .2 _+ 0 .5 4 .6 + 0 .7 6 .0 + 0 .4 30.7 + 2 .7 6.1 +__ 0 .2

T.cucurbitacearum eggs

9 13.7 + 1.1 24 .9 + 1.2 38 .9 _+ 1.7 2 4 0 . 4 + 9 .9 52 .0 + 1.7 o" 12.7 + 1.1 20 .9 + 1.4 36 .0 + 1.1 194.0 +__ 6 .9 52.0 + 1.7

T.cucurbitacearum n y m p h s

q~ 6 .0 + 0 .8 6 .9 ___ 0 .6 14.6 _+ 0 .8 46 .6 + 3 .4 12.0 _+ 0 .4 o" 6 .2 + 0 .8 7 .8 + 1.1 12.1 + 0.3 46 .4 + 4 .9 11.0 + 0 .7

Table 4 shows that different stages of A.gossipi consumed higher numbers of nymphs of T.cucurbitacearum than of T.urticae and the difference was significant. Immatures of either sex of A.gossipi consumed similar numbers of the immatures of the prey.

Regarding the adult stage, cr and 9 of both predator species consumed similar numbers of the prey.

However, it can be concluded that the tetranychid mite, T.cucurbitacearum is a more favourable prey for both predators than the twospotted spider mite, T.urticae. Also it is evident that prey species as well as prey stage affect the predatory effi- ciency, development and rate of oviposition of the predatory mites, A.gossipi and T. mangiferus.

PREDATORY EFFICIENCY OF TWO PHYTOSEIIDS 139

TABLE 4

Average number s o f larvae, n y m p h s o f T . u r t i c a e and n y m p h s o f T . c u c u r b i t a c e a r u m con- s u m e d by d i f f eren t stages o f A . g o s s i p i

Daily average Total

Larva Protonymph Deutonymph Adult

7". urticae larvae

9 3.5 +_ 0.7 7.6 +_ 0.8 9.3 + 0.7 33.3 +_ 1.8 12.3 + 0.3 o" 3.4 _+ 0.7 7.9 _+ 0.7 10.5 + 1.1 32.7 + 1.6 11.4 + 0.2

T. urticae nymphs

9 2.6 + 0.1 4.9 + 0.4 7.8 +_ 0.5 22.2 _+ 1.4 8.3 + 0.3 c, 2.1 + 0.4 4.1 + 0.4 7.3 + 0.8 20.3 +_ 1.4 7.54 _+ 0.3

T.cucurbitacearum nymphs

9 4.7 _ 0.2 7.3 +_ 0.9 11.3 + 0.2 34.4 + 2.5 12.6 + 0.5 e, 5.1 + 0.6 5.1 + 0.9 11.6 + 0.5 31.0 + 2.8 12.4 + 0.5

RI~SUMt~

Influence de l'esp~ce et des stades de la proie sur l'efficacit6 et le d~veloppement de deux acariens phytoseiides

On a 6tudi6 l'effet de l'esp6ce de la proie et de ses diff6rents stades sur l'efficacit6 et la biologie des acariens phytoseiides, Amblyseius gossipi ELSADRY et Typhlodromus mangiferus sp.n. II a 6t6 constat6 que l'alimentation des 2 pr6dateurs avec Tetranyehus cucurbitacearum (SAYED) assure un d6veloppement plus rapide et une f6condit6 plus 61ev6e que leur 61evage sur T.urticae (KOCH). Les diff6rents stades de ces 2 proies produisent des r6ponses diff6rentes dans les activit~s biologiques des 2 acariens pr6dateurs.

R E F E R E N C E S

ELBADRu E.A. & ELBANHAWY, E.M. - - 1968. The effect of non-prey food, mainly pollen on the develop- ment, survival and fecundity of Amblyseius gossipi [Acarina : Phytoseiidae]. -- Entomol. Exp. Appl., 11, 269-272.

ELBADRY, E.A., AFtFI, A.M., ISSA, G.I. & ELBANHAWY, E.M. - - 1968. Effectiveness of the predacious mite Amblyseius gossipi as a predator of three tetranychid mites [Acarina : Phytoseiidae]. - - Z. Angew. Entomol., 62, 186-194.

RASMu A.H. - - 1977. Predatory efficiency and biology of the predatory mite Amblyseius gossipi [Aca- rina : Phytoseiidae] as affected by plant surfaces. - - Entomophaga, 22, 421-423.

RASMY, A.H. & ELBANHAWY, E.M. - - 1974. The phytoseiid mite Phytoseius plumifer as a predator of the eriophyid mite Aceria ficus [Acarina]. - - Entomophaga, 19, 427-430.