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Robert F Luck - One of the best experts on this subject based on the ideXlab platform.
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cellular immune response of brown soft scale Coccus hesperidum l hemiptera coccidae to eggs of metaphycus luteolus timberlake hymenoptera encyrtidae
Biological Control, 2009Co-Authors: Apostolos Kapranas, Robert F Luck, Brian A Federici, Jeffrey J JohnsonAbstract:Abstract The parasitic wasp, Metaphycus luteolus Timberlake, is an endoparasitoid of various soft scale insects including brown soft scale, Coccus hesperidum L. Development of this parasitoid in scale hosts is hindered by encapsulation. In the present study, using transmission and scanning electron microscopy, we show that hemocytes are responsible for encapsulation, which is mediated by the direct deposition of cells and melanin on the surface of M. luteolus eggs. By 12 h post-oviposition, scale hemocytes, presumably granulocytes, aggregate, spread and directly lyse on the surface of parasitoid eggs. This process continues for at least 1 day and results in the gradual formation of a capsule. Two to three days post-oviposition, a melanized capsule is well formed and signs of chemical deposition are evident by examination of the outer surface of the capsule. These results demonstrate that soft scale insects are fully capable of melanotic encapsulation of foreign material mediated by hemocytes.
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host discrimination superparasitism and infanticide by a gregarious endoparasitoid
Animal Behaviour, 2008Co-Authors: Alejandro Tena, Apostolos Kapranas, Ferran Garciamari, Robert F LuckAbstract:When a female parasitoid encounters a previously parasitized host she may reject it or accept and oviposit in/on it (superparasitism), frequently adding one or more eggs after killing some of the offspring in the initial clutch (infanticide). Herein we document these behaviours in a facultatively gregarious endoparasitoid wasp, Metaphycus flavus (Hymenoptera: Encyrtidae), when females encounter unparasitized and parasitized brown soft scales, Coccus hesperidum (Hemiptera: Coccidae), 2 h, 2 days or 4 days after their initial parasitism. We also report the consequences of such behaviours for their offspring survival. Females discriminated unparasitized scales from parasitized scales independent of the time elapsed since the first oviposition and they often oviposited on parasitized scales after killing some of the offspring in the first clutch. Immature parasitoid mortality was a dominant feature of this host–parasitoid interaction and it depended on the occurrence of superparasitism and the time interval between ovipositions. In single clutches, encapsulation of parasitoid eggs was the major source of immature mortality. Encapsulation rates decreased when a second clutch of eggs was added; consequently, superparasitism appears advantageous. When the time interval between ovipositions was long (2–4 days), encapsulation rates decreased again, but most of the younger larvae of the second clutch were consumed by the older larvae of first clutch in superparasitized hosts. Under these circumstances a female should avoid superparasitizing these hosts, or she should kill the eggs or larvae already present in it before allocating a clutch of eggs.
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precise sex ratios manifested by several encyrtid parasitoids hymenoptera encyrtidae of brown soft scale Coccus hesperidum l hemiptera coccidae
Behavioral Ecology and Sociobiology, 2008Co-Authors: Apostolos Kapranas, Joseph G Morse, P Pacheco, L D Forster, Robert F LuckAbstract:We examined whether several facultatively gregarious encyrtid (Hymenoptera: Encyrtidae) endoparasitoids of brown soft scale, Coccus hesperidum L., manifest precise sex allocation under field conditions. Metaphycus luteolus (Timberlake), Metaphycus angustifrons (Compere), Metaphycus stanleyi (Compere), and Microterys nietneri (Motshulsky) evince brood sex ratios that are female-biased and extremely precise (low variance in the number of sons per host). Typically, this sex allocation pattern is attributed to extreme local mate competition (LMC) in which only one foundress exploits a patch of hosts and mating occurs mostly between her offspring. However, such a pattern of sex allocation was not detected for Metaphycus helvolus (Compere). Also, a large proportion of the broods in all five species contained only daughters; thus, an excess of male-only broods was expected if unmated females (i.e., females that can produce only sons) contribute offspring before mating. All-male broods were rare in our samples. This finding coupled with the life history characteristics of these wasps, such as the exploitation of aggregated hosts and the long life span and mobility of males, suggest that nonlocal mating is frequent. Our empirical work suggests that it is advantageous to allocate precise sex ratios in cases in which mating opportunities for males are not restricted to their natal host and/or when multiple foundresses exploit large patches of hosts. Limited theoretical work also supports this prediction but more detailed studies of this taxon’s mating structure and other life history characteristics are necessary to understand their sex allocation decisions.
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survey of brown soft scale Coccus hesperidum l parasitoids in southern california citrus
Biological Control, 2007Co-Authors: Apostolos Kapranas, Joseph G Morse, Lisa Forster, P Pacheco, Robert F LuckAbstract:The parasitoid complex of brown soft scale, Coccus hesperidum L., a multivoltine soft scale, was determined in southern California citrus over the period February 2004–March 2006. The survey was conducted by placing brown soft scale-infested yucca leaves in the canopy of citrus trees and subsequently rearing individually isolated parasitized scales in the laboratory. A total of 14 species parasitized brown soft scale in the field, the most abundant ones belonging to the genus Metaphycus Mercet (75%). The most abundant parasitoid species was Metaphycus angustifrons Compere (38% parasitism), and this is a new record of establishment for this species in California. Coccophagus species accounted for only 11% parasitism. There were important spatio-temporal differences across the parasitoid complex survey locations. We also found that the five most abundant encyrtid parasitoid species showed preferences for scales of different sizes. Our results have implications for biological control of citricola scale, Coccus pseudomagnoliarum (Kuwana), an important pest of citrus in the San Joaquin Valley of central California. Notably, this species is nearly absent in southern California. Brown soft scale is considered to be an alternate host for parasitoids of citricola scale, a univoltine soft scale, at times when the latter species is unavailable for parasitism.
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Responses of Metaphycussp. nr. flavus to semiochemicals released from a scale host, Coccus hesperidum
CHEMOECOLOGY, 2004Co-Authors: Paolo Lo Bue, Stefano Colazza, Lisa D. Forster, Jocelyn G. Millar, Robert F LuckAbstract:Metaphycus sp. nr. flavus (Encyrtidae: Hymenoptera) is a parasitoid species collected from the Mediterranean region which lays its eggs in the immature stages of several economically important soft scale insects (Hemiptera: Coccidae), including brown soft scale, Coccus hesperidum L. (= host insect). Preliminary tests suggested that the parasitoid is most successful in producing offspring when it oviposits in the younger stages of brown soft scale. In Y-olfactometer bioassays measuring wasp choices and residence times, naïve parasitoids were significantly more attracted to yucca leaves infested with 26, 27, or 28 d-old scale than to uninfested leaves, whereas leaves with older (29-30 d-old) scale were no more attractive than uninfested leaves. Parasitoids also spent significantly more time in the arm with yucca leaves infested with 26 d-old scale than in the arm with uninfested leaves. These results are consistent with observations of the parasitoid’s reproductive success on scale of different ages, whereby older scale are more likely to encapsulate the developing eggs of M . sp. nr. flavus females than are younger scale. Further bioassays determined that yucca leaves that had been infested with 26 d-old scale but from which the scale had been removed were as attractive as infested leaves. In contrast, infested yucca leaves from which scale had been removed and the leaves subsequently washed with distilled water were less attractive than infested leaves. Furthermore, the wash water containing scale residues was attractive to female wasps. In total, these results suggest that Metaphycus sp. nr. flavus females utilize volatile, water soluble compounds produced by brown soft scale as cues to locate suitable hosts.
T. Zaviezo - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity of armored scales (Hemiptera: Diaspididae) and soft scales (Hemiptera: Coccidae) in Chile
Scientific Reports, 2017Co-Authors: P. Amouroux, D. Crochard, J.-f. Germain, M. Correa, J. Ampuero, G. Groussier, P. Kreiter, T. Malausa, T. ZaviezoAbstract:Scale insects (Sternorrhyncha: Coccoidea) are one of the most invasive and agriculturally damaging insect groups. Their management and the development of new control methods are currently jeopardized by the scarcity of identification data, in particular in regions where no large survey coupling morphological and DNA analyses have been performed. In this study, we sampled 116 populations of armored scales (Hemiptera: Diaspididae) and 112 populations of soft scales (Hemiptera: Coccidae) in Chile, over a latitudinal gradient ranging from 18°S to 41°S, on fruit crops, ornamental plants and trees. We sequenced the COI and 28S genes in each population. In total, 19 Diaspididae species and 11 Coccidae species were identified morphologically. From the 63 COI haplotypes and the 54 28S haplotypes uncovered, and using several DNA data analysis methods (Automatic Barcode Gap Discovery, K2P distance, NJ trees), up to 36 genetic clusters were detected. Morphological and DNA data were congruent, except for three species ( Aspidiotus nerii , Hemiberlesia rapax and Coccus hesperidum ) in which DNA data revealed highly differentiated lineages. More than 50% of the haplotypes obtained had no high-scoring matches with any of the sequences in the GenBank database. This study provides 63 COI and 54 28S barcode sequences for the identification of Coccoidea from Chile.
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Genetic diversity of armored scales (Hemiptera: Diaspididae) and soft scales (Hemiptera: Coccidae) in Chile
Scientific Reports, 2017Co-Authors: P. Amouroux, D. Crochard, J.-f. Germain, M. Correa, J. Ampuero, G. Groussier, P. Kreiter, T. Malausa, T. ZaviezoAbstract:Scale insects (Sternorrhyncha: Coccoidea) are one of the most invasive and agriculturally damaging insect groups. Their management and the development of new control methods are currently jeopardized by the scarcity of identification data, in particular in regions where no large survey coupling morphological and DNA analyses have been performed. In this study, we sampled 116 populations of armored scales (Hemiptera: Diaspididae) and 112 populations of soft scales (Hemiptera: Coccidae) in Chile, over a latitudinal gradient ranging from 18 degrees S to 41 degrees S, on fruit crops, ornamental plants and trees. We sequenced the COI and 28S genes in each population. In total, 19 Diaspididae species and 11 Coccidae species were identified morphologically. From the 63 COI haplotypes and the 54 28S haplotypes uncovered, and using several DNA data analysis methods (Automatic Barcode Gap Discovery, K2P distance, NJ trees), up to 36 genetic clusters were detected. Morphological and DNA data were congruent, except for three species (Aspidiotus nerii, Hemiberlesia rapax and Coccus hesperidum) in which DNA data revealed highly differentiated lineages. More than 50% of the haplotypes obtained had no high-scoring matches with any of the sequences in the GenBank database. This study provides 63 COI and 54 28S barcode sequences for the identification of Coccoidea from Chile.
Apostolos Kapranas - One of the best experts on this subject based on the ideXlab platform.
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cellular immune response of brown soft scale Coccus hesperidum l hemiptera coccidae to eggs of metaphycus luteolus timberlake hymenoptera encyrtidae
Biological Control, 2009Co-Authors: Apostolos Kapranas, Robert F Luck, Brian A Federici, Jeffrey J JohnsonAbstract:Abstract The parasitic wasp, Metaphycus luteolus Timberlake, is an endoparasitoid of various soft scale insects including brown soft scale, Coccus hesperidum L. Development of this parasitoid in scale hosts is hindered by encapsulation. In the present study, using transmission and scanning electron microscopy, we show that hemocytes are responsible for encapsulation, which is mediated by the direct deposition of cells and melanin on the surface of M. luteolus eggs. By 12 h post-oviposition, scale hemocytes, presumably granulocytes, aggregate, spread and directly lyse on the surface of parasitoid eggs. This process continues for at least 1 day and results in the gradual formation of a capsule. Two to three days post-oviposition, a melanized capsule is well formed and signs of chemical deposition are evident by examination of the outer surface of the capsule. These results demonstrate that soft scale insects are fully capable of melanotic encapsulation of foreign material mediated by hemocytes.
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Sequences of sex allocation and mortality in clutches of Metaphycus parasitoids of soft scale insects and the prevalence of all-female broods
Ecological Entomology, 2009Co-Authors: Apostolos Kapranas, Eric Wajnberg, Robert LuckAbstract:1. In many gregarious or quasi-gregarious parasitoids that experience local mate competition, precise sex ratios with low variance are observed. Precise sex ratios can be achieved by laying male and female eggs in non-random sequences. 2. Developmental mortality can also alter sex ratios of emerging offspring, and subsequently influence sex ratio optima. 3. The present study investigates sex allocation by Metaphycus flavus Howard, M. luteolus Timberlake, and M. angustifrons Compere (Hymenoptera: Encyrtidae), endoparasitoids of soft scale insects, in the laboratory. 4. All three Metaphycus species had precise secondary sex ratios when parasitising brown soft scale, Coccus hesperidum, L. in the laboratory. Moreover, we documented that all three species lay fertilised (= female) eggs first followed by unfertilised (= male) eggs at the end of the oviposition bout. However, there were significant differences in sex allocation sequences among species. 5. Mortality rates of eggs allocated within an oviposition bout also varied considerably, indicating that there is a significant interspecific variation in sequence position-specific mortality. 6. Using a stochastic Monte Carlo simulation approach, we provide evidence that the incidence of all-female broods in these parasitoid wasps appears mainly due to developmental mortality and not due to decisions by the ovipositing female. In two species the prevalence of all-female broods was independent of clutch size, contrary to what is expected from theory. The influence of mortality on optimal sex allocation in these parasitoids is discussed.
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host discrimination superparasitism and infanticide by a gregarious endoparasitoid
Animal Behaviour, 2008Co-Authors: Alejandro Tena, Apostolos Kapranas, Ferran Garciamari, Robert F LuckAbstract:When a female parasitoid encounters a previously parasitized host she may reject it or accept and oviposit in/on it (superparasitism), frequently adding one or more eggs after killing some of the offspring in the initial clutch (infanticide). Herein we document these behaviours in a facultatively gregarious endoparasitoid wasp, Metaphycus flavus (Hymenoptera: Encyrtidae), when females encounter unparasitized and parasitized brown soft scales, Coccus hesperidum (Hemiptera: Coccidae), 2 h, 2 days or 4 days after their initial parasitism. We also report the consequences of such behaviours for their offspring survival. Females discriminated unparasitized scales from parasitized scales independent of the time elapsed since the first oviposition and they often oviposited on parasitized scales after killing some of the offspring in the first clutch. Immature parasitoid mortality was a dominant feature of this host–parasitoid interaction and it depended on the occurrence of superparasitism and the time interval between ovipositions. In single clutches, encapsulation of parasitoid eggs was the major source of immature mortality. Encapsulation rates decreased when a second clutch of eggs was added; consequently, superparasitism appears advantageous. When the time interval between ovipositions was long (2–4 days), encapsulation rates decreased again, but most of the younger larvae of the second clutch were consumed by the older larvae of first clutch in superparasitized hosts. Under these circumstances a female should avoid superparasitizing these hosts, or she should kill the eggs or larvae already present in it before allocating a clutch of eggs.
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precise sex ratios manifested by several encyrtid parasitoids hymenoptera encyrtidae of brown soft scale Coccus hesperidum l hemiptera coccidae
Behavioral Ecology and Sociobiology, 2008Co-Authors: Apostolos Kapranas, Joseph G Morse, P Pacheco, L D Forster, Robert F LuckAbstract:We examined whether several facultatively gregarious encyrtid (Hymenoptera: Encyrtidae) endoparasitoids of brown soft scale, Coccus hesperidum L., manifest precise sex allocation under field conditions. Metaphycus luteolus (Timberlake), Metaphycus angustifrons (Compere), Metaphycus stanleyi (Compere), and Microterys nietneri (Motshulsky) evince brood sex ratios that are female-biased and extremely precise (low variance in the number of sons per host). Typically, this sex allocation pattern is attributed to extreme local mate competition (LMC) in which only one foundress exploits a patch of hosts and mating occurs mostly between her offspring. However, such a pattern of sex allocation was not detected for Metaphycus helvolus (Compere). Also, a large proportion of the broods in all five species contained only daughters; thus, an excess of male-only broods was expected if unmated females (i.e., females that can produce only sons) contribute offspring before mating. All-male broods were rare in our samples. This finding coupled with the life history characteristics of these wasps, such as the exploitation of aggregated hosts and the long life span and mobility of males, suggest that nonlocal mating is frequent. Our empirical work suggests that it is advantageous to allocate precise sex ratios in cases in which mating opportunities for males are not restricted to their natal host and/or when multiple foundresses exploit large patches of hosts. Limited theoretical work also supports this prediction but more detailed studies of this taxon’s mating structure and other life history characteristics are necessary to understand their sex allocation decisions.
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survey of brown soft scale Coccus hesperidum l parasitoids in southern california citrus
Biological Control, 2007Co-Authors: Apostolos Kapranas, Joseph G Morse, Lisa Forster, P Pacheco, Robert F LuckAbstract:The parasitoid complex of brown soft scale, Coccus hesperidum L., a multivoltine soft scale, was determined in southern California citrus over the period February 2004–March 2006. The survey was conducted by placing brown soft scale-infested yucca leaves in the canopy of citrus trees and subsequently rearing individually isolated parasitized scales in the laboratory. A total of 14 species parasitized brown soft scale in the field, the most abundant ones belonging to the genus Metaphycus Mercet (75%). The most abundant parasitoid species was Metaphycus angustifrons Compere (38% parasitism), and this is a new record of establishment for this species in California. Coccophagus species accounted for only 11% parasitism. There were important spatio-temporal differences across the parasitoid complex survey locations. We also found that the five most abundant encyrtid parasitoid species showed preferences for scales of different sizes. Our results have implications for biological control of citricola scale, Coccus pseudomagnoliarum (Kuwana), an important pest of citrus in the San Joaquin Valley of central California. Notably, this species is nearly absent in southern California. Brown soft scale is considered to be an alternate host for parasitoids of citricola scale, a univoltine soft scale, at times when the latter species is unavailable for parasitism.
Joseph G Morse - One of the best experts on this subject based on the ideXlab platform.
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precise sex ratios manifested by several encyrtid parasitoids hymenoptera encyrtidae of brown soft scale Coccus hesperidum l hemiptera coccidae
Behavioral Ecology and Sociobiology, 2008Co-Authors: Apostolos Kapranas, Joseph G Morse, P Pacheco, L D Forster, Robert F LuckAbstract:We examined whether several facultatively gregarious encyrtid (Hymenoptera: Encyrtidae) endoparasitoids of brown soft scale, Coccus hesperidum L., manifest precise sex allocation under field conditions. Metaphycus luteolus (Timberlake), Metaphycus angustifrons (Compere), Metaphycus stanleyi (Compere), and Microterys nietneri (Motshulsky) evince brood sex ratios that are female-biased and extremely precise (low variance in the number of sons per host). Typically, this sex allocation pattern is attributed to extreme local mate competition (LMC) in which only one foundress exploits a patch of hosts and mating occurs mostly between her offspring. However, such a pattern of sex allocation was not detected for Metaphycus helvolus (Compere). Also, a large proportion of the broods in all five species contained only daughters; thus, an excess of male-only broods was expected if unmated females (i.e., females that can produce only sons) contribute offspring before mating. All-male broods were rare in our samples. This finding coupled with the life history characteristics of these wasps, such as the exploitation of aggregated hosts and the long life span and mobility of males, suggest that nonlocal mating is frequent. Our empirical work suggests that it is advantageous to allocate precise sex ratios in cases in which mating opportunities for males are not restricted to their natal host and/or when multiple foundresses exploit large patches of hosts. Limited theoretical work also supports this prediction but more detailed studies of this taxon’s mating structure and other life history characteristics are necessary to understand their sex allocation decisions.
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survey of brown soft scale Coccus hesperidum l parasitoids in southern california citrus
Biological Control, 2007Co-Authors: Apostolos Kapranas, Joseph G Morse, Lisa Forster, P Pacheco, Robert F LuckAbstract:The parasitoid complex of brown soft scale, Coccus hesperidum L., a multivoltine soft scale, was determined in southern California citrus over the period February 2004–March 2006. The survey was conducted by placing brown soft scale-infested yucca leaves in the canopy of citrus trees and subsequently rearing individually isolated parasitized scales in the laboratory. A total of 14 species parasitized brown soft scale in the field, the most abundant ones belonging to the genus Metaphycus Mercet (75%). The most abundant parasitoid species was Metaphycus angustifrons Compere (38% parasitism), and this is a new record of establishment for this species in California. Coccophagus species accounted for only 11% parasitism. There were important spatio-temporal differences across the parasitoid complex survey locations. We also found that the five most abundant encyrtid parasitoid species showed preferences for scales of different sizes. Our results have implications for biological control of citricola scale, Coccus pseudomagnoliarum (Kuwana), an important pest of citrus in the San Joaquin Valley of central California. Notably, this species is nearly absent in southern California. Brown soft scale is considered to be an alternate host for parasitoids of citricola scale, a univoltine soft scale, at times when the latter species is unavailable for parasitism.
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sex ratios in field populations of two parasitoids hymenoptera chalcidoidea of Coccus hesperidum l homoptera coccidae
Oecologia, 1998Co-Authors: Julio S Bernal, Robert F Luck, Joseph G MorseAbstract:We tested several assumptions and predictions of host-quality-dependent sex allocation theory (Char- nov et al. 1981) with data obtained for the parasitoid Metaphycus stanleyi Compere on its host, brown soft scale (Coccus hesperidum L.), in a California citrus grove and in the laboratory. Scales ceased growing after pa- rasitization by M. stanleyi. Thus, M. stanleyi may gauge host quality (asize) at oviposition. Host size positively influenced adult parasitoid size, and parasitoid size in turn influenced adult longevity of M. stanleyi. However, parasitoid fitness gains with host size and adult size were similar in males versus females. Sex allocation to indi- vidual hosts by M. stanleyi depended on host size; fe- males consistently emerged from larger hosts than males. Host size was important in a relative sense; the mean host sizes of females versus males, and of solitary versus gregarious parasitoids varied with the available host size distribution. The oAspring sex ratio of M. stanleyi reflected the available host size distribution; the sex ratio of emerging parasitoids varied with the avail- able host size distribution. We did not detect a ''critical host size'' below which males emerged, and above which females emerged; rather, only females emerged from hosts in the upper size range, and a variable ratio of males and females emerged from hosts in the lower size range. We conclude that the sex ratio of field popula- tions of M. stanleyi is driven largely by the available size distribution of C. hesperidum. In addition, we tested predictions resulting from theoretical analyses of sex allocation in autoparasitoids with data obtained on Coccophagus semicircularis (Forster) parasitizing brown soft scale in the field. The sex ratio of C. semicircularis was consistently and strongly female biased (ca. 90% females). Based on available theoretical analyses, we suggest that this sex ratio pattern may have resulted from a very low encounter rate of secondary hosts coupled with a strong time limitation in C. semicircularis females. This explanation was the most plausible given constraints stemming from the detection of secondary hosts, their variable location within primary hosts, and their handling times. Finally, the size of hosts which yielded single versus multiple parasitoids, and the sizes of these parasitoids, were compared. These comparisons suggested that: (1) M. stanleyi females gauge host sizes precisely, and in terms of female oAspring; thus a fitness penalty is not incurred by females which share a host, while males benefit from sharing a host, and; (2) in- stances where multiple C. semicircularis emerged from a single host were probably the result of parasitism by diAerent females, or during diAerent encounters by a single female.
Agnieszka Najda - One of the best experts on this subject based on the ideXlab platform.
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differences in the sugar composition of the honeydew of polyphagous brown soft scale Coccus hesperidum hemiptera sternorrhyncha coccoidea feeding on various host plants
European Journal of Endocrinology, 2011Co-Authors: Katarzyna Golan, Agnieszka NajdaAbstract:Plant chemical composition is an important determinant of host plant-insect interactions. For many insects sugars are the main factors determining the acceptability of a plant. This study investigated changes in plant chemical composition and differences in sugar composition of different host plants induced by the feeding of Coccus hesperidum L. (Hemiptera: Sternorrhyncha: Coccoidea). Present in plant extracts and honeydew there were three monosaccharide sugars: glucose, fructose and arabinose, and one disaccharide - sucrose. Arabinose was only found in extracts of Ficus benjamina plants. The sugar content of the honeydew was greater than in the extracts of control plants and lower than that in the extracts of infested plants. The honeydew collected from C. hesperidum feeding on the three plant species differed significantly in sugar content. Extracts of coccid infested plants of the three species used in this study contained more sugar than the un-infested control plants. The results show that honeydew composition of scale insects differ and the differences reflect the chemical composition of the host plants.