JAE 125 (2001)

J. Appl. Ent. 125, 121±124 (2001) Ó 2001 Blackwell Wissenschafts-Verlag, Berlin ISSN 0931-2048 Rearing and breeding of the Moroccan maroccanus (Thunberg) (Orthop., ) under laboratory conditions

E. Quesada-Moraga and C. Santiago-A lvarez Ca tedra de Entomologõ a Agrõ cola y Forestal, Departamento de Ciencias y Recursos Agrõ colas y Forestales, E.T.S. de Ingenieros Agro nomos y de Montes, Universidad de Co rdoba, Co rdoba, Spain

Abstract: The objective of the present work was to design a rearing method for the Moroccan or Mediterranean locust and to breed it. The duration of the post-embryonic development from N1 to adult ranged between 35 and 38 days, independently of whether nymphs were reared at constant temperature or in cages with incandescent light bulbs that a€ord heat for thermo-regulation. In contrast, the number of nymphs reaching the adult stage was directly related to the power of the bulb from 0 to 60 W. The rearing density did not a€ect the survival and developmental time of nymphs over the range 100±400 nymphs per cage. The survival of D. maroccanus nymphs under optimal conditions, which were a 60 W bulb and 400 nymphs per cage, was around 60%. The mean number of egg- pods per female ranged between 2.6 and 3.5, and no di€erence was observed among rearing densities, with 16 pairs per cage being the optimal breeding condition. The number of eggs per egg pod ranged from 15 to 25, the egg viability from 20 to 50% and the adult longevity from 30 to 40 days. Eggs deposited by D. maroccanus females reared under these laboratory conditions were viable and thus the present study has `closed' the life cycle of this species for the ®rst time. The rearing method developed in this study will provide elements for studies of biology and physiology and it can be used in the design of new, environmentally sound pest management measures.

1 Introduction method for rearing D. maroccanus under laboratory conditions and a breeding method. Progress in entomological research and success of pest management programmes depend on our ability to rear and establish colonies in the laboratory (SINGH and MOORE, 1985). Dociostaurus maroccanus is 2 Materials and methods an important plague locust of the Mediterranean One hundred egg-pods were collected from a ®eld in a region that has been frequently investigated (UVAROV, permanent breeding area of la Serena (Badajoz, Spain) 1928; CANÄ IZO and MORENO-MA RQUEZ, 1950; MERTON, (38°55¢N, 5°29¢W) in June 1997. Egg-pods were placed at 1959; LATCHININSKY and LAUNOIS-LUONG, 1992). the bottom of 210 ml styrofoam cups (15 per cup) covered Nevertheless, a rearing method for this species has by 5 cm of moistened vermiculite (1.5 ml distilled water/1 g not been developed, probably due to its extremely long vermiculite). They were incubated at 25°C for about embryonic development that extends for more than 40 days to complete anatrepsis (diapause stage), then at 9 months (BODENHEIMER and SHULOV, 1951); thus 10°C for 30±40 days to accelerate diapause development and termination and ®nally at 25°C for 15±20 days until post-embryonic stages are available only during 3  months per year when they can be found in natural hatching (QUESADA-MORAGA and SANTIAGO-ALVAREZ, 1999). conditions. Rearing of the was carried out in an insectary Recent studies have pointed out that the two arrests regulated at 26°C, 60% relative humidity, under a of the embryonic development of this species (BODEN- 13 h light : 11 h dark photoperiod. Two sizes of rearing HEIMER and SHULOV, 1951) can be overcome by cages made of wooden frames and metallic mesh were used: laboratory manipulation (QUESADA-MORAGA and 50 cm ´ 50 cm ´ 50 cm for nymphs and 30 cm ´ 30 cm ´ SANTIAGO-A LVAREZ, 1999, 2000). Furthermore, the 30 cm for adults. Nymphs were allowed to move vertically in diapause can be overcome by a period of cold exposure a heat gradient provided by 40 W or 60 W incandescent light to around 10°C and the total embryonic development bulbs that were mounted in the middle of the upper wall of the cages. A metallic mesh tube (8 cm diameter ´ 45 or shortened to 80±90 days (QUESADA-MORAGA and 27 cm high in nymphs and adult cages, respectively) was SANTIAGO-A LVAREZ, 1999, 2000). The e€ective man- placed under the bulb to permit the vertical movement of agement of the embryonic development aims at estab- nymphs. The temperature regime for each combination of lishing a stock colony in the laboratory that will cage size and bulb power is presented in table 1. An provide elements for studies about biology, physiology additional experiment of rearing at constant temperature and pest control measures. In this article we present a

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Table 1. Temperatures Light bulb power (°C) on and within cages Cage size Location 40 W 60 W with varying light bulb powers. Temperatures were 50 cm ´ 50 cm ´ 50 cm Base of the cage 28 29 Lower surface of the bulb 42 49 recorded with a copper Maximum on side of cage 31 33 constantan thermocouple (0.127 mm diameter) 30 cm ´ 30 cm ´ 30 cm Base of the cage 27 32 Lower surface of the bulb 42 49 Maximum on side of cage 33 36

was made for comparison. The locusts were fed with dry Table 3. Survival (% of nymphs reaching the adult wheat bran, wheat seedlings and cabbage. stage) and development time (number of days from star At hatching, nymphs were placed in cages for monitoring of ®rst instar to imaginal moult) for D. maroccanus and recording survival percentage and instar duration. The nymphs reared under di€erent densities in cages with duration of each instar was monitored from the time at which 60 W bulbs 50% of the nymphs reached a particular instar until 50% of the nymphs reached the following instar. Newly emerged adults were transferred from 50 cm ´ Adult stage Development 50 cm ´ 50 cm cages to the smaller 30 cm ´ 30 cm ´ 30 cm NC n % time ones. Plastic containers (800 ml) ®lled with sterile wet sand were placed at the bottom of the adult cages for oviposition. 100 2 57.0 ‹ 1.4 57.0 ‹ 1.4 35.5 ‹ 0.7 Egg-pods were removed every day and kept in 210 ml 400 2 235.5 ‹ 37.4 58.9 ‹ 9.4 34.5 ‹ 2.1 styrofoam cups covered by wet vermiculite. Groups of three C, number of cages; n, number of insects. styrofoam cups were placed in self-sealing plastic bags and incubated as previously described until hatching. Longevity, ®rst copulation, pre-oviposition period and egg production 400 nymphs, the survival of nymphs was 60% and the were monitored for the full life of the adults. Statistical development time 35 days (table 3). analysis of data was carried out using the program Statistic Neither the rearing density nor the bulb power 14.1 for Windows. a€ected the duration of each instar. The second instar was the shortest (4±6 days) and the ®fth instar the longest (9±12 days). The ®rst and fourth instars were 3 Results synchronous (6±8 days) and shorter than the third one The duration of the post-embryonic development of (7±9 days). D. maroccanus, ranged between 36 and 38 days, and Sixty-two newly moulted adults, males and females, was independent of whether the nymphs were reared at coming from nymphs reared in cages with 60 W bulbs, constant temperature or in cages that a€ord heat for were removed to adult cages with 60 W bulbs in thermo-regulation (table 2). In contrast, the number of graded numbers of pairs from 1 to 16 (table 4). nymphs reaching the adult stage was directly related to Independently of the number of pairs in the cages, the power of the bulb, increasing from 10.8% at the ®rst copulation occurred 5 days after the imaginal constant temperature to 25.3% in cages with 40 W moult and the pre-oviposition period extended to bulbs, and to 64.6% in cages with 60 W bulbs 10 days. The mean number of egg-pods per female (table 2). On the other hand, the e€ect of rearing ranged between 2.6 and 3.5, and no di€erence was density on survival and development time of nymphs observed among rearing densities (table 4). was tested in cages with 60 W bulbs (table 3). It was Pods deposited by females in cages with one and two clearly observed that these two parameters did not pairs were damaged during the counting of eggs, but di€er between cages with 100 nymphs and those with the pods from cages with four, eight and 16 pairs were manipulated in order to force embryonic development for studying the viability of eggs. Egg viability was near 50% in two cages and 20% in the other (table 4). Table 2. Survival (% of nymphs reaching the adult Adult longevity, ranged from 30 to 40 days and was stage) and development time (number of days from star independent of the number of pairs in the cage of ®rst instar to imaginal moult) for D. maroccanus (table 4). Similar longevity values were observed when nymphs reared under di€erent densities and temperature the adults from nymphs reared in cages with 40 W gradients bulbs were transferred to adult cages with 40 or 60 W bulbs, and when the adults from nymphs reared in Adult stage cages with 60 W bulbs were transferred to adult cages Development NCWp n % time with 40 W bulbs. In contrast, the adults from nymphs reared in cages without bulbs and transferred to cages 300 4 o€ 32.3 ‹ 11.7 10.8 ‹ 3.9 37.5 ‹ 2.9 at constant temperature had a maximum longevity 300 1 40 76 25.3 38.0 of 7 days. 300 1 60 194 64.6 36.0 A new experiment was designed in order to provide C, number of cages; Wp, bulb power in Watts; n, number of a more detailed analysis of the in¯uence of the heat insects. source within the cages on the ecacy of the rearing Laboratory production of Moroccan locust Dociostaurus maroccanus 123

Table 4. Longevity and Longevity reproductive parameters of Egg-pods/ D. maroccanus reared in the N Males Females female Eggs/pod Egg hatchability laboratory under di€erent 1 32.5 ‹ 0.7 a 34.0 ‹ 0.0 a 3.5 ‹ 0.7 ± number of pairs (N) 2 35.0 ‹ 2.3 a 35.3 ‹ 26.7 a 2.8 ‹ 0.3 ± 4 40.7 ‹ 16.3 a 37.5 ‹ 10.0 a 3.0 ‹ 0.7 22.5 ‹ 6.4 43.4 ‹ 6.5 8 29.3 ‹ 11.4 b 38.9 ‹ 10.9 a 2.6 ‹ 0.8 16.7 ‹ 8.6 17.1 ‹ 7.0 16 36.0 ‹ 11.6 a 39.1 ‹ 9.3 a 2.6 ‹ 0.1 16.7 ‹ 6.1 46.3 ‹ 32.5 Data are mean ‹ standard deviation, means within columns with the same letter are not signi®cantly di€erent (least signi®cant di€erence (LSD) at the 5% level).

The total duration of D. maroccanus development until the adult stage is similar to those of Taeniopoda eques (Burmeister) (Orthop., Acrididae) and Schistoc- erca gregaria (ForskaÊ l) (Orthop., Acrididae) (SINGH 3and MOORE, 1985;WHITMAN, 1986) but it is around 10 days shorter than that of Melanoplus sanguinipes 4(F) (Orthop., Acrididae) (SINGH and MOORE, 1985). The full life cycle of this species can be achieved in around 120±130 days, considering the duration of the post-embryonic development, the pre-oviposition per- iod and the embryonic development (QUESADA- MORAGA and SANTIAGO-A LVAREZ, 1999, 2000). The adult longevity permits an additional period of 20 days Fig. Survival rate of D. maroccanus ®fth instar nymphs to get a higher number of egg pods for the following under di€erent conditions for thermo-regulation generation. It is possible consequently to get at least two generations per year in the laboratory. Neverthe- less, the management of the embryonic development method. Mortality data was recorded daily from six can allow an overlapping of egg hatching, and hence a cages, each containing around 100 nymphs collected continuous supply of post-embryonic stages. from a ®eld. Two cages remained at constant tem- Variations in the rate of development were not perature for the full experiment, four cages had 60 W recorded at di€erent rearing densities. We selected a bulbs during the light period, with the bulbs of two of maximum density of 400 nymphs per cage because a these cages switched o€ 15 days after the beginning of higher number resulted in too many problems for the 2experiment (®g.). The survival rate of nymphs reared at daily manipulation schedule, and a minimum of 100 constant temperature decreased quickly towards a nymphs because a lower number was considered as a minimum that was reached after 20 days. In contrast, waste of volume within the cage, diet materials and the survival rate of nymphs reared in cages with 60 W energy. Under our particular conditions, the optimum bulbs decreased slightly towards a minimum that was rearing condition would be 400 insects per cage reached after 40 days. When the bulb was switched o€ because it o€ers greater colonies without negative 15 days after the beginning of the experiment, the interference in the survival of the nymphs due to survival ratio su€ered a sharp decline (®g.). competition for food or heat. It would probably be necessary to consider higher di€erences between rea- ring densities to detect any di€erences in the rate of 4 Discussion development as observed in other locust (NORRIS, 1950, 1952; GILLET, 1975; NOLTE, 1976). This is the ®rst record on the breeding of D. marocc- The survival of D. maroccanus nymphs under anus under laboratory conditions. In a previous optimal conditions was higher than 50% as frequently attempt, the species was maintained under laboratory observed in other locusts rearing (SINGH and MOORE, conditions but the full life cycle of the species was not 1985; SCHMIDT and ALBUÈ TZ, 1994; HABTEWOLD et al., closed (GRADOJEVIC , 1960). 1995). Therefore, our rearing method seems to be Our results clearly show that the presence of an extra adequate for this locust, although an improvement in heat source within the cages, the bulb, for thermo- the method could be achieved by changing wheat regulation is indispensable to the rearing of D. marocc- seedlings for annual graminea from D. maroccanus anus. Therefore, the rearing of this locust at constant breeding areas. temperature is not viable. Although 40 W bulbs have The di€erent numbers of adult pairs were selected in lower electric consumption than 60 W bulbs, their use order to optimize equipment, diet materials and leads to a reduction in survival and so they should not energy. We did not select more than 16 pairs per cage be used. This decrease in the survival is probably due due to manipulation diculties in the daily schedule. to the reduction of the power of the heat source that The results show that the optimum number of pairs in does not allow locusts to thermo-regulate under the cages is 16 because it allows an increase in the optimal conditions (CASEY, 1988). availability of egg-pods for the next generation without 124 E. Quesada-Moraga and C. Santiago-A lvarez causing any negative e€ects in all the life cycle longicornis, under laboratory conditions and demogra- parameters of the adults. The longevity of D. marocc- phic e€ects on the pathogen Nosema locustae. Biol. Cont. anus adults reared under laboratory conditions is 5, 497±502. similar to that of Locusta migratoria (L) (Orthop., LATCHININSKY, A. V.; LAUNOIS-Luong, M. H., 1992: Le cricket marocain, Dociostaurus maroccanus (Thunberg, Acrididae) (NORRIS, 1950) but 20 days shorter than 1815) dans la partie orientale de son aire de distribution. those of Aiolopus thalassinus (Fabr.) (Orthop., Acrid- In: Etude monographique a L'ex-URSS et aux pays idae) (SCHMIDT and OTHMAN, 1994) and S. gregaria proches. Saint-Pe tersbourg: CIRAD-GERDAT-PRI- (SCHMIDT and ALBUÈ TZ, 1994). The number of egg-pods FAS: Montpellier/VIZR: 270 pp. deposited by D. maroccanus females reared under MERTON, F. H., 1959: Studies on the ecology of the optimal conditions was higher than that observed 5 Moroccan locust in Cyprus. Anti-Locust Bull. 34, 123 pp. under natural conditions where no more than two NOLTE, D. J., 1976: Locustol and its analogues. J. egg-pods are normally deposited (MERTON, 1959; Physiol. 22, 833±838. LATCHININSKY and LAUNOIS-LUONG, 1992; QUESADA- NORRIS, M. J., 1950: Reproduction in the African migratory MORAGA, 1998). This increase of number of egg-pods locust (L. migratoria migratorioides) in relation to density under laboratory conditions is a common feature as 6 and phase. Anti-Locust Bull. 6, 50 pp. NORRIS, M. J., 1952: Reproduction in the desert locust has been clearly established (UVAROV, 1966). The (S. gregaria) in relation to density and phase. Anti-Locust present results indicate that eggs deposited by Bull. 13, 51 pp. D. maroccanus females reared under laboratory con- QUESADA-MORAGA, E., 1998: Biologõ a y ecologõ adela ditions are viable and this study has `closed' the life reproduccio n y desarrollo embrionario de la langosta cycle of this species for the ®rst time. mediterra nea Dociostaurus maroccanus (Thunberg) y su The rearing method developed in this study can lead posible interferencia como estrategia de lucha. PhD to greater progress in the study of the Mediterranean Thesis. Universidad de Co rdoba, Spain. or Moroccan locust and to the design new environ- QUESADA-MORAGA, E.; SANTIAGO-A LVAREZ, C., 1999: mentally sound pest management measures. Induccio n de la salida de la diapausa en la langosta mediterra nea Dociostaurus maroccanus (Thunberg). J. Research 8, 13±16. Acknowledgements QUESADA-MORAGA, E.; SANTIAGO-A LVAREZ, C., 2000: Ther- mal requirements for embryonic development for the This research was supported by the Spanish Commission Mediterranean locust, Dociostaurus maroccanus. Physiol. Interministerial de Ciencia y Tecnologõ a (CICYT) Grant 8 Entomol. 25, 191±195. AGF94±0145. E.Q.-M. expresses his thanks to the Ministerio SCHMIDT, G. H.; ALBUÈ TZ, R., 1994: Laboratory studies on de Educacio n y Ciencia, Direccio n General de Investigacio n pheromone and reproduction in the desert locust Cientõ ®ca y Te cnica, for Grant AP94 24247227. The authors Schistocerca gregaria (Forsk). J. Appl. Entomol. 118, would like to thank Professor P PENER, Hebrew Univer- AUL 378±391. sity of Jerusalem, for critically reviewing the manuscript and SCHMIDT, G. H.; OTHMAN, K. S. A., 1994: Studies of the Mr M BATTANY, IAS CSIC Co rdoba, for correcting the ARK in¯uence of pheromones on the reproduction of virgin English phraseology. and mated females of the acridid Aiolopus thalassinus (Fabr.) (Insecta: Orthoptera: acrididae). Zool. Anzeiger References 233, 75±116. SINGH, P.; MOORE, R. F., 1985: Handbook of Insect Rearing, BODENHEIMER, F. S.; SHULOV, A., 1951: Egg development Vol. I. Amsterdam: Elsevier Science Publisher B.V. and diapause in the Moroccan locust. Bull. Res. Council UVAROV, B. P., 1928: Locust and . A Hand- Israel 1, 59±75. book for their Study and Control. London: The Imperial CANÄ IZO, J.; MORENO-MA RQUEZ, V., 1950: Biologõ a y ecologõ a Bureau of Entomology. de la langosta mediterra nea o marroquõ (Dociostaurus UVAROV, B. P., 1966: Grasshoppers and Locust, Vol. I. maroccanus Thunb.). Bol. Pat. Veg. y Ent. Agrõ c. 17, 209± London: Cambridge University Press. 242. WHITMAN, D. W., 1986: Developmental thermal require- CASEY, M. T., 1988: Thermoregulation and heat exchange. ments for the Taeniopoda eques (Orthoptera: Adv. Insect Physiol. 20, 119±146. acrididae). Ann. Entomol Soc. Am. 79, 711±714. GILLET, S. D., 1975: The action of the gregarisation

pheromone on ®ve non-behavioral characters of phase Authors' address: E. QUESADA-MORAGA, Professor Dr D. polymorphism of the desert locust Schistocerca gregaria CANDIDO SANTIAGO-A LVAREZ (corresponding author), Ca te- ForskaÈ l. Acrida 4, 137±149. dra de Entomologõ a Agrõ cola y Forestal, Departamento de GRADOJEVIC , M., 1960: Some laboratory experiments on Ciencias y Recursos Agrõ colas y Forestales, E.T.S. de phases in the Moroccan locust (Dociostaurus maroccanus Ingenieros Agro nomos y de Montes, Universidad de Co rdo- Thunb). Zashtita Bilja 57±58, 129±142. ba, Apartado 3048, 14080 Co rdoba, Spain. HABTEWOLD, T.; LANDIN, J.; WENNERGEN, V.; BERGMAN,K. E-mail: [email protected] O., 1995: Life table for the tef grasshopper Aiolopus