scholarly journals Ecological Drivers and Sex-Based Variation in Body Size and Shape in the Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae)

Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Yufei Zhou ◽  
Juanita Rodriguez ◽  
Nicole Fisher ◽  
Renee A. Catullo
Keyword(s):  
Body Size ◽  
Fluctuating Asymmetry ◽  
Morphological Traits ◽  
Geographic Distance ◽  
Fruit Fly ◽  
Wing Shape ◽  
The Body ◽  
Economic Losses ◽  
Pest Species ◽  
Bactrocera Tryoni

The Queensland fruit fly (Bactrocera tryoni; Q-fly) is an Australian endemic horticultural pest species, which has caused enormous economic losses. It has the potential to expand its range to currently Q-fly-free areas and poses a serious threat to the Australian horticultural industry. A large number of studies have investigated the correlation between environmental factors and Q-fly development, reproduction, and expansion. However, it is still not clear how Q-fly morphological traits vary with the environment. Our study focused on three morphological traits (body size, wing shape, and fluctuating asymmetry) in Q-fly samples collected from 1955 to 1965. We assessed how these traits vary by sex, and in response to latitude, environmental variables, and geographic distance. First, we found sexual dimorphism in body size and wing shape, but not in fluctuating asymmetry. Females had a larger body size but shorter and wider wings than males, which may be due to reproductive and/or locomotion differences between females and males. Secondly, the body size of Q-flies varied with latitude, which conforms to Bergmann’s rule. Finally, we found Q-fly wing shape was more closely related to temperature rather than aridity, and low temperature and high aridity may lead to high asymmetry in Q-fly populations.

scholarly journals Selection on morphological traits and fluctuating asymmetry by a fungal parasite in the yellow dung fly

2017 ◽  
Author(s):  
Wolf U. Blanckenhorn
Keyword(s):  
Body Size ◽  
Fungal Infection ◽  
Fluctuating Asymmetry ◽  
Large Body ◽  
The Body ◽  
Female Size ◽  
Adult Body Size ◽  
Scathophaga Stercoraria ◽  
Evolutionary Response ◽  
Adult Body

AbstractA Preprint reviewed and recommended by Peer Community Evolutionary Biology: http://dx.doi.org/10.24072/pci.evolbiol.100027Evidence for selective disadvantages of large body size remains scarce in general. Previous phenomenological studies of the yellow dung fly Scathophaga stercoraria have demonstrated strong positive sexual and fecundity selection on male and female size. Nevertheless, the body size of flies from a Swiss study population has declined by almost 10% from 1993 to 2009. Given substantial heritability of body size, this negative evolutionary response of an evidently positively selected trait suggests important selective factors being missed (e.g. size-selective predation or parasitism). A periodic epidemic outbreak of the fungus Entomophthora scatophagae allowedassessment of selection exerted by this parasite fatal to adult flies. Fungal infection varied over the season from ca. 50% in the cooler and more humid spring and autumn to almost 0% in summer. The probability of dying from fungal infection increased with adult body size. All infected females died before laying eggs, so there was no fungus impact on female fecundity beyond its impact on mortality. Large males showed the typical mating advantage in the field, but this pattern of positive sexual selection was nullified by fungal infection. Mean fluctuating asymmetry of paired appendages (legs, wings) did not affect the viability, fecundity or mating success of yellow dung flies in the field. This study demonstrates rare parasite-mediated disadvantages of large adult body size in the field. Reduced ability to combat parasites such as Entomophthora may be an immunity cost of large size in dung flies, although the hypothesized trade-off between fluctuating asymmetry, a presumed indicator of developmental instability and environmental stress, and immunocompetence was not found here.

scholarly journals Efficiency of RNA interference is improved by knockdown of dsRNA nucleases in tephritid fruit flies

Open Biology ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 190198 ◽  
Author(s):  
Alison Tayler ◽  
Daniel Heschuk ◽  
David Giesbrecht ◽  
Jae Yeon Park ◽  
Steve Whyard
Keyword(s):  
Rna Interference ◽  
Fruit Fly ◽  
Target Cells ◽  
Pest Species ◽  
Melanin Synthesis ◽  
Bactrocera Tryoni ◽  
Double Stranded Rna ◽  
Rnai Efficiency ◽  
Gene Transcripts ◽  
Tephritid Fruit Flies

RNA interference (RNAi) in insects is routinely used to ascertain gene function, but also has potential as a technology to control pest species. For some insects, such as beetles, ingestion of small quantities of double-stranded RNA (dsRNA) is able to knock down a targeted gene's expression. However, in other species, ingestion of dsRNA can be ineffective owing to the presence of nucleases within the gut, which degrade dsRNA before it reaches target cells. In this study, we observed that nucleases within the gut of the Queensland fruit fly ( Bactrocera tryoni ) rapidly degrade dsRNA and reduce RNAi efficacy. By complexing dsRNA with liposomes within the adult insect's diet, RNAi-mediated knockdown of a melanin synthesis gene, yellow , was improved significantly, resulting in strong RNAi phenotypes. RNAi efficiency was also enhanced by feeding both larvae and adults for several days on dsRNAs that targeted two different dsRNase gene transcripts. Co-delivery of both dsRNase-specific dsRNAs and yellow dsRNA resulted in almost complete knockdown of the yellow transcripts. These findings show that the use of liposomes or co-feeding of nuclease-specific dsRNAs significantly improves RNAi inhibition of gene expression in B. tryoni and could be a useful strategy to improve RNAi-based control in other insect species.

Testing Rensch’s rule in Acanthoscelides macrophthalmus, a seed-feeding beetle infesting Leucaena leucocephala plants

2019 ◽  
Vol 97 (4) ◽  
pp. 304-311
Author(s):  
M.N. Rossi ◽  
E.B. Haga
Keyword(s):  
Body Size ◽  
Leucaena Leucocephala ◽  
Morphological Traits ◽  
Genetic Basis ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Males And Females

Rensch’s rule states that males vary more in size than females when body size increases. The main cause of Rensch’s rule has been credited to sexual selection. However, different degrees of plasticity between the sexes have also been proven to be useful for describing variations in sexual size dimorphism, particularly within an intraspecific context. For insects, in general, this rule has rarely been tested within species. Here, we tested whether Acanthoscelides macrophthalmus (Schaeffer, 1907) (Coleoptera: Chrysomelidae: Bruchinae) followed Rensch’s rule when individuals emerged from seeds immediately after fruit collection and when they were reared for one generation, by measuring three morphological traits. Rensch’s rule was not followed for any of the morphological traits. Variations in body size were similar in males and females for bruchines that first emerged from seeds and for those that were reared for one generation. These findings suggest that environmental conditions (e.g., temperature, humidity, and seasonality) are unlikely to drive differential plasticity in males and females of this seed-feeding beetle. It is possible that changes in the body size of A. macrophthalmus have a genetic basis. However, regardless of whether variations in body size have a genetic basis, our findings provide no support for Rensch’s rule.

scholarly journals Can multitrophic interactions shape morphometry, allometry, and fluctuating asymmetry of seed-feeding insects?

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241913
Author(s):  
Tamires Camila Talamonte de Oliveira ◽  
Angelo Barbosa Monteiro ◽  
Lucas Del Bianco Faria
Keyword(s):  
Body Size ◽  
Food Web ◽  
Fluctuating Asymmetry ◽  
Body Shape ◽  
Morphological Structure ◽  
The Body ◽  
Reproductive Capacity ◽  
Body Structure ◽  
Parasitism Rate ◽  
Seed Biomass

Body size is commonly associated with biological features such as reproductive capacity, competition, and resource acquisition. Many studies have tried to understand how these isolated factors can affect the body pattern of individuals. However, little is known about how interactions among species in multitrophic communities determine the body shape of individuals exploiting the same resource. Here, we evaluate the effect of fruit infestation, parasitism rate, and seed biomass on size, allometric and asymmetric patterns of morphological structures of insects that exploit the same resource. To test it, we measured 750 individuals associated with the plant Senegalia tenuifolia (Fabaceae), previously collected over three consecutive years. Negative allometry was maintained for all species, suggesting that with increasing body size the body structure did not grow proportionally. Despite this, some variations in allometric slopes suggest that interactions in a multitrophic food web can shape the development of these species. Also, we observed a higher confidence interval at higher categories of infestation and parasitism rate, suggesting a great variability in the allometric scaling. We did not observe fluctuating asymmetry for any category or species, but we found some changes in morphological structures, depending on the variables tested. These findings show that both allometry and morphological trait measurements are the most indicated in studies focused on interactions and morphometry. Finally, we show that, except for the fluctuating asymmetry, each species and morphological structure respond differently to interactions, even if the individuals play the same functional role within the food web.

scholarly journals Population differences and domestication effects on mating and remating frequencies in Queensland fruit fly

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Khandaker Asif Ahmed ◽  
Heng Lin Yeap ◽  
Gunjan Pandey ◽  
Siu Fai Lee ◽  
Phillip W. Taylor ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Reproductive Strategies ◽  
Natural Variation ◽  
Captive Breeding ◽  
Strain Differences ◽  
Fruit Fly ◽  
Inhibitory Effect ◽  
Pest Species ◽  
Bactrocera Tryoni ◽  
Male Genotype

AbstractFemales of many insect species are unreceptive to remating for a period following their first mating. This inhibitory effect may be mediated by either the female or her first mate, or both, and often reflects the complex interplay of reproductive strategies between the sexes. Natural variation in remating inhibition and how this phenotype responds to captive breeding are largely unexplored in insects, including many pest species. We investigated genetic variation in remating propensity in the Queensland fruit fly, Bactrocera tryoni, using strains differing in source locality and degree of domestication. We found up to threefold inherited variation between strains from different localities in the level of intra-strain remating inhibition. The level of inhibition also declined significantly during domestication, which implied the existence of genetic variation for this trait within the starting populations as well. Inter-strain mating and remating trials showed that the strain differences were mainly due to the genotypes of the female and, to a lesser extent, the second male, with little effect of the initial male genotype. Implications for our understanding of fruit fly reproductive biology and population genetics and the design of Sterile Insect Technique pest management programs are discussed.

scholarly journals Morphology and Morphometry of Caeca in the Tufted Duck Aythya Fuligula

2009 ◽  
Vol 54-55 (1-4) ◽  
pp. 21-31
Author(s):  
Ewa Działa-Szczepańczyk ◽  
Anna Charuta
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Fluctuating Asymmetry ◽  
The Body ◽  
Asymmetry Coefficient ◽  
Tarsus Length ◽  
Tufted Duck ◽  
Morphology And Morphometry ◽  
Sternum Length

Morphology and Morphometry of Caeca in the Tufted Duck Aythya Fuligula In this study, we examined the caeca of 44 individuals of Tufted Duck (Aythya fuligula): 29 males (23 adult and 6 young) and 15 females (8 adult and 7 young). We analyzed the correlations between lengths of left (CLL) and right (CRL) caeca vs. the dimensions of the bird's body: body weight (BW), body length (BL), sternum length (SL) and tarsus length (TL), in relation to the sex of the animals. We also analyzed the asymmetry of caeca and determined its direction and strength, using a fluctuating asymmetry coefficient. Despite the observed sexual dimorphism in the body size, we found neither sex-related differences in the length of caeca, nor any significant correlation between the CLL and CRL vs. body size (BW, BL, SL, TL). 42 birds (94.5%) were asymmetrical with respect to the length of caeca, and in 37 (84.1%) the left caecum was longer. The fluctuating asymmetry coefficient for the length of these organs in the examined group was 0.413.

Effect of adult chill treatments on recovery, longevity and flight ability of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

2010 ◽  
Vol 101 (1) ◽  
pp. 63-71 ◽  
Author(s):  
O.L. Reynolds ◽  
B.A. Orchard
Keyword(s):  
Body Size ◽  
Recovery Time ◽  
Fruit Fly ◽  
Mass Rearing ◽  
Bactrocera Tryoni ◽  
Inundative Release ◽  
Flight Ability ◽  
Sucrose Diet ◽  
Recovery Times ◽  
Release Method

AbstractControl of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), populations or outbreaks may be achieved through the mass-rearing and inundative release of sterile B. tryoni. An alternative release method is to release chilled adult sterile fruit flies to decrease packaging and transport requirements and potentially improve release efficiencies. Two trials were conducted to determine the effect of chilling on the performance of two separate batches of adult B. tryoni, fed either a protein and sucrose diet or sucrose only diet. The first trial compared chill times of 0, 0.5, 2 and 4 h; the second trial compared chill times of 0, 2, 4, 8 and 24 h. Overall, there was little or no affect of chilling on the recovery, longevity and flight ability of B. tryoni chilled at 4°C. Recovery time can take up to 15 min for chilled adult flies. There was no effect of chill time on longevity although females generally had greater longevity on either diet compared with males. Propensity for flight was not adversely affected by chilling at the lower chill times in trial 1; however, in trial 2, adults fed on a protein and sucrose diet had a decreased tendency for flight as the chilling time increased. Fly body size did not affect recovery times although the smaller adult B. tryoni in trial 1 had significantly reduced longevity compared to the larger adults in trial 2. Implications of these findings for B. tryoni SIT are discussed.

scholarly journals A fungal parasite selects against body size but not fluctuating asymmetry in Swiss subalpine yellow dung flies

2021 ◽  
Vol 5 ◽  
pp. 27-35
Author(s):  
Wolf U. Blanckenhorn
Keyword(s):  
Body Size ◽  
Fungal Infection ◽  
Fluctuating Asymmetry ◽  
Large Body ◽  
The Body ◽  
Female Size ◽  
Large Body Size ◽  
Scathophaga Stercoraria ◽  
Evolutionary Response ◽  
Study Population

Evidence for selective disadvantages of large body size remains scarce in general. Previous studies of the yellow dung fly Scathophaga stercoraria have demonstrated strong positive sexual and fecundity selection on male and female size. Nevertheless, the body size of flies from a Swiss study population has declined by ~10% 1993–2009. Given substantial heritability of body size, this negative evolutionary response of an evidently positively selected trait suggests important selective factors being missed. An episodic epidemic outbreak of the fungus Entomophthora scatophagae permitted assessment of natural selection exerted by this fatal parasite. Fungal infection varied over the season from ~50% in the cooler and more humid spring and autumn to almost 0% in summer. The probability of dying from fungal infection increased with adult fly body size. Females never laid any eggs after infection, so there was no fungus effect on female fecundity beyond its impact on mortality. Large males showed their typical mating advantage in the field, but this positive sexual selection was nullified by fungal infection. Mean fluctuating asymmetry of paired appendages (legs, wings) did not affect the viability, fecundity or mating success of yellow dung flies in the field. This study documents rare parasite-mediated disadvantages of large-sized flies in the field. Reduced ability to combat parasites such as Entomophthora may be an immunity cost of large body size in dung flies, although the hypothesized trade-off between fluctuating asymmetry, a presumed indicator of developmental instability and environmental stress, and immunocompetence was not found here.

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