The current state of natural foci of swarming locusts (Orthoptera,Acrididae) in Turkmenistan

Climatic changes and anthropogenic impact on natural ecosystems result in the growth of locust populations. The general characteristic of the spatial distribution of the Moroccan (Dociostaurus maroccanus Thunb.), Italian (Calliptamus italicus L.), and Asian migratory (Locusta migratoria migratoria L.) locusts in Turkmenistan are given.     

Moroccan locust Dociostaurus maroccanus (Thunberg, 1815): a faunistic rarity or an important economic pest?

The Moroccan locust, Dociostaurus maroccanus (Thunberg), was traditionally considered as one of the most dangerous agricultural pests in the Mediterranean (s.l.) zone. Its broad polyphagy, extreme voracity, enormous fecundity and capability to migrate in swarms made it a major enemy of agriculturists from the Canary Islands to Afghanistan. However, outbreaks of the Moroccan locust seem to have been more frequent in the past and, in many regions, the species has become rare. Climatic factors, in particular the amount of spring rainfall, are critical for the developmental cycle of D. maroccanus. However, anthropogenic factors appear to have the most powerful effect on the locust's population dynamics. On the one hand, deforestation and overgrazing create the necessary prerequisites for colonization by the Moroccan locust. On the other hand, converting grasslands into croplands makes the habitat totally unsuitable for the insect because females can lay eggs into undisturbed soil. These two conflicting tendencies appear to govern the current evolution of Moroccan locust populations, their manifestations being different according to the geographical zone. Although in some regions (e.g. in many European countries) D. maroccanus has lost its formerly high economic importance, in others (North African and central Asian countries) the species continues to flourish and may even increase its pest status.     

Natural foci of the Moroccan locust (<Emphasis Type="Italic">Dociostaurus maroccanus</Emphasis>, Orthoptera,Acrididae) in Turkmenistan and their current state

The current state of natural foci and the population dynamics of the Moroccan locust Dociostaurus maroccanus in Turkmenistan are described. The slope aspect, micro-relief, plant cover condition, and the degree of anthropogenic impact were considered in natural landscapes. The locations of the natural foci were described using a Garmin eTrex GPS device. The causes and features of changes in the altitudinal and latitudinal distribution of the species’ natural foci in the Kopet Dagh and Koyten Dagh mountains during the second half of the XX and early XXI centuries are revealed. Both lower and upper range limit extensions of the locust foci are shown to have been due to xerophytization of the mountain ecosystems because of excessive pasture use and climate aridization. As a result, Turkmenistan presently supports 15 areas of D. maroccanus outbreaks instead of 12 areas known previously.     

Diapause termination and post-diapause development in the Mediterranean locust Dociostaurus maroccanus (Orth., Acrididae) under field conditions

Abstract: Diapause termination and post-diapause development of the Mediterranean or Moroccan locust, Dociostaurus maroccanus , were studied in the permanent breeding area of la Serena (Badajoz) in southern Spain during 1991–92 and 1997–98. By the second half of autumn, diapause development has been completed and the eggs have acquired the ability to resume morphogenesis, catatrepsis and hatching. The last week of November was determined to be the critical time to begin recording degree-days as a basis for the development of hatch prediction models. Using a previously developed temperature model for embryonic development of D. maroccanus , accurate predictions of hatching were performed for the two study seasons. The results of this investigation will facilitate in developing an efficient system for the management of the Moroccan locust.     

Entomopathogenic Fungi Associated with Natural Populations of the Moroccan Locust Dociostaurus maroccanus (Thunberg) (Orthoptera: Gomphocerinae) and Other Acridoidea in Spain

The entomopathogenic fungi Beauveria bassiana Vuill . and Metarhizium anisopliae (Metschnikoff) have been found in natural populations of the Moroccan locust Dociostaurus maroccanus (Thunberg) and other species of acridoids that cohabit the same locust breeding areas in southern Spain . Infection levels of B. bassiana on insects collected in the field and maintained under laboratory conditions were relatively high (1 . 6 - 20 . 5%) . The prevalence of the disease extended from spring to summer in the three consecutive years monitored . A local isolate of this fungus demonstrated high virulence (LD = 440 conidia / insect) against the 50 locust D. maroccanus in the laboratory bioassay . The relatively wide host range of B. bassiana and its adaptation to the dry and hot conditions dominating the locust breeding area suggest that this isolate could be considered in the development of a biological control programme against D. maroccanus.     

Behavioural phase polyphenism in the Australian plague locust (Chortoicetes terminifera)

Swarming and the expression of phase polyphenism are defining characteristics of locust species. Increases in local population density mediate morphological, physiological and behavioural changes within individuals, which correlate with mass marching of juveniles in migratory bands and flying swarms of adults. The Australian plague locust (Chortoicetes terminifera) regularly forms migratory bands and swarms, but is claimed not to express phase polyphenism and has accordingly been used to argue against a central role for phase change in locust swarming. We demonstrate that juvenile C. terminifera express extreme density-dependent behavioural phase polyphenism. Isolated-reared juveniles are sedentary and repelled by conspecifics, whereas crowd-reared individuals are highly active and are attracted to conspecifics. In contrast to other major locust species, however, behavioural phase change does not accumulate across generations, but shifts completely within an individual''s lifetime in response to a change in population density.     

Synthesis of adipokinetic hormone (AKH-I) in the locust brain

Methanol extracts of vitellogenic female locust brains contain two factors that inhibit protein synthesis in fat body tissue excised from such individuals. One of these factors (BI) elicits lipid mobilization when injected into adult male locusts. The retention times of BI on an RP-18 column and on an RP-4 column are identical to those of synthetic locust adipokinetic hormone (AKH-I) on each of these columns. Half maximal inhibition of protein synthesis in excised adult locust fat bodies is exerted by 0.05 brain extract equivalents of BI, which is equivalent to activity elicited by 1.5 pmol of AKH-I, as previously determined by AKH-radioimmunoassay. Enzymatic hydrolysis of the N-terminal pyroglutamate, followed by amino acid sequence analysis, indicates that the structure of BI is similar to that of the decapeptide AKH-I synthesized in the glandular lobe of the locust corpora cardiaca (CC). Incorporation of [5-³H]tryptophan into BI of locust brains incubated in vitro indicates that the AKH-I present in the brain is synthesized in situ and is not transported from the CC. Similar incorporation of radiolabel into AKH-I is obtained when excised CC are incubated in vitro.     

Additions to the Limoniidae and Pediciidae fauna of Morocco,with an updated checklist (Diptera,Tipuloidea)

Eighteen species of Limoniidae and two species of Pediciidae are recorded for the first time in Morocco, of which 15 species are new to North Africa. An updated checklist of Moroccan short-palped craneflies (Limoniidae and Pediciidae) is appended, containing 73 species in 25 genera.     

Histopathology of secondary infections of Malpighamoeba locustae (Protozoa,Amoebidae) in the desert locust, Schistocerca gregaria (Orthoptera,Acrididae)

Schistocerca gregaria, the desert locust, harbors the protozoan parasite Malpighamoeba locustae. Twelve to 16 days after infection, trophozoites begin to multiply rapidly inside the Malpighian tubules of the gut. Swelling and rupture of the Malpighian tubules leads to the release of large numbers of cysts and trophozoites into the hemocoel. The classic insect defense response results in these cysts and trophozoites becoming encapsulated by the hemocytes of the host. Hemocytes of the phagocytic type become attached to, and lodged between, a variety of tissues and organs of the locust and black hemocytic capsules are produced. The extent to which the different tissues are involved is graded. Some tissues are completely blackened and encapsulated by masses of hemocytes but others are so lightly affected that the small specks of blackened pigment they lay down are discernible only on close examination. The trophozoites themselves do not divide outside the Malpighian tubules. The graded response in the host tissues is related to (1) the presence of sheets and lobes of fat body and (2) the presence of phagocytic hemocytes.     

Effects of black locust (Robinia pseudoacacia) on soil properties in the loessial gully region of the Loess Plateau, China

Black locust (Robinia pseudoacacia) has been widely planted in the Loess Plateau for soil and water conservation. The effects of black locust on soil properties has significant role in land use and ecosystem management. However, this beneficial effect has been little studied in the Loess Plateau. The soil properties below black locust and native grass growing in Nanxiaohe and Wangdonggou watersheds, located in the loessial gully region of the Loess Plateau, were studied for changes in soil properties after establishment of black locust. The black locust significantly increased soil cation exchange capacity, organic carbon, total nitrogen, nitrate, and carbon:nitrogen and carbon:phosphorus (P) ratios, as well as some enzymes like alkaline phosphatase and invertase in 0–20 cm or 0–80 cm depths of soil compared to the native grassland in Nanxiaohe and Wangdonggou watersheds. However, the effects on ammonium, total P, and extractable P and potassium were not consistent in both watersheds. There were more obvious differences in soil properties between black locust land and grassland for Nanxiaohe watershed than for Wangdonggou watershed, suggesting that the effects of black locust on most soil properties increase with black locust age. The results indicate that black locust has potential to improve soil properties in the loessial gully region of the Loess Plateau and the improvements were greater in long-term than middle-term black locust stands.     

Interactions of two insect pathogens, Paranosema locustae (Protista: Microsporidia) and Metarhizium acridum (Fungi: Hypocreales), during a mixed infection of Locusta migratoria (Insecta: Orthoptera) nymphs

Locusta migratoria nymphs were fed Paranosema locustae spores and/or surface-treated with Metarhizium acridum 3 (assay 1), 6 (assay 2) or 9 days (assay 3) post microsporidia application (p.m.a.). These three dates corresponded to the key phases of P. locustae development: (a) mass proliferation, (b) transition to sporogenesis and (c) onset of spore maturation, respectively. As a result, locust mortality due to mixed treatment increased slower, equally and faster, as compared to mortality expected from the combination of two pathogens in assays 1-3, respectively. However, a statistically significant difference in survival times was observed only in assay 3, indicating that only at the phase of spore maturation microsporidia drastically increase locust susceptibility to fungal infection. Analysis of perished nymphs showed that fungal treatment 3 days p.m.a. impeded development of microsporidia. Fungal sporulation on locust cadavers was not affected by co-occurring microsporidiosis.     

On the pronymphal stage in the migratory locust (Locusta migratoria, Orthoptera, Acrididae)

The structure of the integument, somatic and visceral muscles, midgut, and Malpighian tubules were investigated at the late stages of the embryonic and early postembryonic development of the migratory locust, Locusta migratoria, to assess the organization of its pronymphal stage. In its morphogenetic features, the vermiform locust larva sometimes called the pronymph corresponds to the first nymphal instar covered with the second embryonic cuticle which has not been shed. Since the first-instar locust nymphs before and after the shedding of this embryonic cuticle differ significantly in many morphological characters, two consecutive phases of this nymphal instar can be distinguished: the first phase existing from the moment of development of the third embryonic cuticle to the shedding of the second one; the second phase existing from the shedding of the second embryonic cuticle to the formation of the cuticle of the second nymphal instar. Since the pronymphal stage should precede the nymph stage, it may be concluded that the pronymph of the locust is fully embryonized and covered with the second embryonic cuticle, which is also typical of other insects with hemimetabolous development (Konopová and Zrzavý, 2005). Therefore, it would be erroneous to refer to the vermiform first-instar nymph as the pronymph, because the two stages are separated by molting and formation of a new cuticle.     

Preliminary characterisation of locust diuretic peptide (DP-1) and another corpus cardiacum peptide (LCCP)

A simple two step HPLC purification protocol is described for one of the locust diuretic peptides (DP-1) and a second corpus cardiacum peptide (LCCP) of unknown function. DP-1 and LCCP are extracted from corpora cardiaca in 20% aqueous methanol (v/v), and applied to a high performance size-exclusion chromatography (HPSEC) column, from which DP-1 and LCCP co-elute in a fraction designated F7/8; this corresponds to a relative molecular mass of ca 6000–7000. Without sample concentration, F7/8 (2 ml) is applied directly onto a wide-pore reversed-phase HPLC column; LCCP and DP-1 are eluted in ca 12 and 20 min respectively on an increasing linear gradient of 0.5% min, starting at 30% acetonitrile. The diuretic activity of the DP-1 material was confirmed using the cAMP assay (Morgan and Mordue, 1985a, Insect Biochem.15, 247–257).DP-1 and LCCP were isolated from ca 650 locusts using the above procedures for sequence analysis by gas-phase sequencing. The low amount of DP-1 purified allowed only a partial and fragmentary sequence to be determined; insufficient material was available for amino acid analysis. The higher amount of LCCP allowed a partial sequence determination of residues 1–40. The titre of DP-1 in locust CC is calculated to be 1.7–2.1 pmol/CC.     

A broadly tuned odorant receptor in neurons of trichoid sensilla in locust,Locusta migratoria

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. Odorant receptors (ORs) on the membrane of chemosensory neurons are believed to be key molecules in sensing exogenous chemical cues. ORs in different species of insects are diverse and should tune a species to its own specific semiochemicals relevant to their survival. The orthopteran insect, locust (Locusta migratoria), is a model hemimetabolous insect. There is very limited knowledge on the functions of locust ORs although many locust OR genes have been identified in genomic sequencing experiments. In this paper, a locust OR, LmigOR3 was localized to neurons housed in trichoid sensilla by in situ hybridization. LmigOR3 was expressed as a transgene in Drosophila trichoid olfactory neurons (aT1) lacking the endogenous receptor Or67d and the olfactory tuning curve and dose-response curves were established for this locust receptor. The results show that LmigOR3 sensitizes neurons to ketones, esters and heterocyclic compounds, indicating that LmigOR3 is a broadly tuned receptor. LmigOR3 is the first odorant receptor from Orthoptera that has been functionally analyzed in the Drosophila aT1 system. This work demonstrates the utility of the Drosophila aT1 system for functional analysis of locust odorant receptors and suggests that LmigOR3 may be involved in detecting food odorants, or perhaps locust body volatiles that may help us to develop new control methods for locusts.     

Présence de l’éocrinoïde Ascocystites Barrande (Echinodermata,Blastozoa) dans l’Ordovicien supérieur (Caradoc) de l’Anti-Atlas (Maroc) : premières données

Family Ascocystitidae, defined and established by Georges Ubaghs in 1967, includes a single genus, Ascocystites. This genus was described and figured for the first time by Barrande in 1887, from Bohemian specimens. Thereafter, specimens brought close to Ascocystites or assigned to this genus were described starting from samples collected in Bohemia in the Armorican Massif or in Portugal. The new specimens were collected in Morocco in the Eastern Anti-Atlas, within the formation of Izzeguirene of Caradoc age. The studied material includes several sandy slabes often containing many well-preserved and almost complete individuals. These levels gather individuals of various sizes, corresponding to various stages of development. The morphological study in progress should allow a specific attribution by comparison with the Bohemian and Armorican forms actually known. The Moroccan material has, in addition, the advantage of corresponding to associations of several Echinodermata groups, rich in individuals, allowing a taphonomic and possibly paleoenvironmental study. Biostratigraphically, Ascocystitidae are actually known between Middle (Armorican Massif and Portugal) and Upper Ordovician (Bohemia and now Morocco). The discovery of Ascocystitidae in the Moroccan Anti-Atlas extends their distribution, within gondwanian domain, during Middle and Upper Ordovician.     

Familial mediterranean fever (FMF) in Moroccan Jews: Demonstration of a founder effect by extended haplotype analysis

Familial Mediterranean fever (FMF) is an autosomal recessive disease causing attacks of fever and serositis. The FMF gene (designated “MEF”) is on 16p, with the gene order 16cen–D16S80–MEF–D16S94–D16S283–D16S291–16pter. Here we report the association of FMF susceptibility with alleles at D16S94, D16S283, and D16S291 among 31 non-Ashkenazi Jewish families (14 Moroccan, 17 non-Moroccan). We observed highly significant associations at D16S283 and D16S291 among the Moroccan families. For the non-Moroccans, only the allelic association at D16S94 approached statistical significance. Haplotype analysis showed that 18/25 Moroccan FMF chromosomes, versus 0/21 noncarrier chromosomes, bore a specific haplotype for D16S94–D16S283–D16S291. Among non-Moroccans this haplotype was present in 6/26 FMF chromosomes versus 1/28 controls. Both groups of families are largely descended from Jews who fled the Spanish Inquisition. The strong haplotype association seen among the Moroccans is most likely a founder effect, given the recent origin and genetic isolation of the Moroccan Jewish community. The lower haplotype frequency among non-Moroccan carriers may reflect differences both in history and in population genetics.     

Artificial miniaturization causes eggs laid by crowd-reared (gregarious) desert locusts to produce green (solitarious) offspring in the desert locust, Schistocerca gregaria

The mechanism underlying the phase-dependent polyphenism in hatchling body coloration was studied by testing for a possible causal relationship with egg size in the desert locust, Schistocerca gregaria. Crowd-reared (gregarious) females typically produce large, black offspring, whereas females reared in isolation (solitarious) deposit small, green offspring. We first tested for possible genetic differences in the role of egg foam by washing or separating eggs from two strains of locust. No solitarizing effect was found in either of the strains tested, supporting a previous finding, using another laboratory strain, to show that the hatchling body coloration and size are pre-determined in the ovary of the mother and no egg foam factor is involved in the control of the hatchling body coloration. Topical application of fenoxycarb, a juvenile hormone analog (JHA), and implantation of extra corpora allata (CA), taken from Locusta migratoria, caused gregarious female adults of S. gregaria to produce small eggs. Some eggs laid by CA-implanted females produced green hatchlings. All large eggs chosen among those deposited by gregarious females produced black hatchlings. When eggs were either kept on dry filter paper at nearly saturated relative humidity during embryogenesis or pricked with a needle so that some egg yolk was squeezed out, some produced small, green hatchlings. These results suggested that the amount of egg yolk or the availability of yolk material may determine the body coloration of hatchlings.     

The analysis of biogenic amines in the thoracic nervous system of the locust,Schistocerca gregaria,by gas-chromatography negative ion chemical ionization mass spectrometry (GC-NICIMS)

Biogenic amines in single ventral thoracic nerve cords of the locust, Schistocerca gregaria, have been identified and quantified by an extraction-derivatization procedure involving their reaction with ditrifluoromethylbenzoyl chloride (DTFMB) in the aqueous phase followed by extraction into an organic solvent, hydrolysis of phenolic esters and conversion of free hydroxyl groups to trimethylsilyl ethers. Subsequent analysis of these DTFMB-TMS derivatives by GC-NICIMS revealed that the molecular ion carried most (> 60%) of the ion current which made the method highly specific and gave a limit of detection below the picogram level. This publication establishes unequivocally that the principal amines in locust ventral thoracic nerve cord are p-tyramine, p-octopamine, dopamine and noradrenaline. 5-Hydroxytryptamine was determined using a previously published GC-NICIMS technique (Markey et al., Biomed. Mass Spectromet. 7, 301–304, 1981).     

Seasonal Fluctuations of Lectins in Barks of Elderberry (Sambucus nigra) and Black Locust (Robinia pseudoacacia)

Elderberry (Sambucus nigra) and black locust (Robinia pseudoacacia) agglutinins, which are abundantly present in the bark of both species, display seasonal fluctuations with regard to their content in this tissue. These seasonal changes result apparently from a circa-annual rhythm of lectin accumulation and depletion during autumn and spring, respectively. Because the bark of trees can be considered as a type of vegetative storage tissue, the results suggest that bark lectins behave as typical storage proteins.     

Spatial differences in the radial growth responses of black locust (Robinia pseudoacacia Linn.) to climate on the Loess Plateau,China

The black locust (Robinia pseudoacacia Linn.) is the dominant tree species in the “grain for green” project on the Loess Plateau (LP) of China, and brings many ecological benefits to this planted region. However, there are concerns regarding its suitability as a plantation forest species in different regions of the LP. We used a dendroclimatological approach to investigate the radial growth response of black locust to varying climate in two sites on the LP with differing precipitation gradients. We took tree-ring samples from black locust in Yongshou County (in the semi-humid southern LP) and Shenmu County (in the semi-arid northern LP), and developed tree-ring width (TRW) chronologies for each. We performed moving correlation analyses between TRW chronologies and aggregated thermal (maximum temperature (TMX), minimum temperature (TMN), mean temperature (TMP)) and hydroclimatic factors (precipitation, self-calibrated Drought Severity Index (scPDSI), and humidity). The results demonstrated the increased influence of thermal factors during autumn, and the generally decreased influence of hydroclimatic factors on black locust radial growth in Yongshou, compared with the decreasing influence of thermal factors (during all seasons) and increasing influence of hydroclimatic factors (precipitation during summer, scPDSI and humidity during autumn) on black locust radial growth in Shenmu. The results indicated that black locust radial growth might benefit from the current climatic conditions in the southern LP. However, black locust radial growth stressed by water availability in the northern LP, which may reduce its vitality and productivity as climate warms in the future. These results have implications for regional forestry planning and ecological restoration strategies on the LP.