The Coordination of Insect Imaginal Discs and the Regulation and Evolution of Complex Worker Caste Systems of Ants

2019 ◽  
pp. 197-224
Author(s):  
Sophie Koch ◽  
Ehab Abouheif
Keyword(s):  
Imaginal Discs ◽  
Worker Caste

scholarly journals Nano-CT characterization reveals coordinated growth of a rudimentary organ necessary for soldier development in the antPheidole hyatti

2021 ◽  
Author(s):  
Sophie Koch ◽  
Rui Tahara ◽  
Angelly Vasquez-Correa ◽  
Ehab Abouheif
Keyword(s):  
Imaginal Disc ◽  
Larval Growth ◽  
Three Dimensional ◽  
Imaginal Discs ◽  
Minor Worker ◽  
Differential Growth ◽  
Larval Size ◽  
Worker Caste ◽  
Regulatory Functions ◽  
Coordination Patterns

AbstractThe growth of imaginal discs in holometabolous insects is coordinated with larval growth to ensure the symmetrical and proportional development of the adult appendages. In ants, the differential growth of these discs generates distinct castes – the winged male and queen castes and the wingless worker caste. In the hyperdiverse ant genusPheidole, the worker caste is composed of two morphologically distinct subcastes: small minor workers and larger, big-headed soldiers. Although these worker subcastes are completely wingless, soldier larvae develop rudimentary forewing discs that are necessary for generating the disproportionate head-to-body scaling of the big-headed soldier subcaste. However, it remains unclear whether rudimentary forewing discs in soldier larvae are coordinated with other imaginal discs, and whether disc growth and coordination patterns vary between the minor worker and soldier subcastes. Here we show, using quantitative nano-CT three-dimensional analyses, that growth of the soldier rudimentary forewing discs is coordinated with the increase in volume of the leg and eye-antennal (head) discs as well as with larval size. We found that the growth rate of the rudimentary forewing discs differs from the leg discs but is similar to the growth of the head (eye-antennal) discs relative to larval size, suggesting that growth of each type of imaginal disc may be differentially regulated. In addition to their larger size, the soldier eye-antennal discs increase in width as they undergo morphogenesis to generate the characteristic shape of the large soldier head, suggesting that the rudimentary forewing discs may regulate their patterning in addition to their growth. Finally, we observe little growth of the leg and eye-antennal discs during the bipotential stage, while in minor worker development these discs grow at similar rates to one another in coordination with larval size to generate the smaller minor worker subcaste. Our results suggest that rudimentary organs with regulatory functions may participate in new patterns of inter-organ coordination and regulation to produce novel phenotypes and complex worker caste systems. We provide characterization of larval development and imaginal disc growth and morphogenesis with the aim of highlighting this as an emerging system for the study of rudimentary organs during development and evolution.

Insecticidal Activities of the Leaf Extract of the Invasive Alien Plant, Chromolaena odorata (L.) (Asteraceae) Against Macrotermes species (Termites)

2019 ◽  
Vol 35 (1) ◽  
pp. 145-153
Author(s):  
O. Uyi, ◽  
I.G. Amolo ◽  
A.D. Adetimehin
Keyword(s):  
Leaf Extract ◽  
Insect Pests ◽  
Chromolaena Odorata ◽  
Leaf Extracts ◽  
Alien Plant ◽  
Biological Efficacy ◽  
Invasive Alien Plant ◽  
Impregnation Technique ◽  
Aqueous Leaf Extract ◽  
Worker Caste

Several studies have demonstrated the biological efficacy of leaf, stem and root powders or extracts of Chromolaena odorata (L.) King and Robinson against insect pests but those that are focused on the biological efficacy of aqueous leaf extracts against Macrotermes species are scanty. Current management of termites with synthetic insecticides is being discouraged due to human and environmental hazards. Therefore, the insecticidal effectiveness of aqueous leaf extract C. odorata against Macrotermes species was investigated. Five concentrations (0, 2.5, 5.0, 7.5 and 10.0% (w/v)) of the aqueous extract of C. odorata plant were evaluated for repellency and toxicity on the worker caste of Macrotermes species following standard procedures. The filter paper impregnation technique was used for the bioassay. Percentage repellency was monitored for 30 minutes and mortality recorded at 12, 24 and 36 hours post exposure. The leaf extract of C. odorata significantly repelled 95% of Macrotermes species at the highest concentration of 10% (w/v) after 30 minutes post treatment exposure. Mortality of Macrotermes species was independent of treatment concentration, but dependent on duration of exposure. All treatment concentrations of aqueous leaf extract of C. odorata caused significant mortality against Macrotermes species ranging between 94% and 98% compared to the control; indicating very great potential for adoption and use in the management of Macrotermes species.

scholarly journals Impact of “non-lethal” tarsal clipping on bumble bees (Bombus vosnesenskii) may depend on queen stage and worker size

2021 ◽  
Author(s):  
John M. Mola ◽  
Clara Stuligross ◽  
Maureen L. Page ◽  
Danielle Rutkowski ◽  
Neal M. Williams
Keyword(s):  
Genetic Material ◽  
Population Monitoring ◽  
First Year ◽  
Negative Effects ◽  
Worker Size ◽  
Monitoring Tools ◽  
Individual Survival ◽  
Body Sizes ◽  
Negative Effect ◽  
Worker Caste

Abstract Recent bumble bee declines have prompted the development of novel population monitoring tools, including the use of putatively non-lethal tarsal clipping to obtain genetic material. However, the potential side effects of tarsal clipping have only been tested in the worker caste of a single domesticated species, prompting the need to more broadly test whether tarsal clipping negatively affects sampled individuals. To determine if tarsal clipping reduces queen survivorship and colony establishment, we collected wild queens of Bombus vosnesenskii and clipped tarsi from a single leg of half the individuals. We reared captive queens and estimated survivorship and nest establishment success. We also clipped tarsi of workers from a subset of colonies across a range of body sizes. We found no consistent negative effect of clipping on queen survival. In the first year, clipped nest-searching queens suffered heavy mortality, but there was no effect on foraging queens. The following year, we found no effect of clipping on queen survival or establishment. Clipping did not reduce overall worker survival but reduced survivorship for those in the smallest size quartile. Implications for insect conservation Our findings suggest tarsal clipping does not have consistent negative effects on individual survival. However, our results varied with queen behavioral state, year, and worker size, suggesting differences within and among species and interactions with landscape stressors warrant further study. In the interim, we recommend researchers and conservationists minimize the use of tarsal clipping for sensitive species, populations, or small workers except in cases of exceptional scientific need.

scholarly journals Isolation of genes active during hormone-induced morphogenesis in Drosophila imaginal discs.

1986 ◽  
Vol 261 (12) ◽  
pp. 5575-5583
Author(s):  
J E Natzle ◽  
A S Hammonds ◽  
J W Fristrom
Keyword(s):  
Imaginal Discs

scholarly journals Oligomerization and endocytosis of Hedgehog is necessary for its efficient exovesicular secretion

2015 ◽  
Vol 26 (25) ◽  
pp. 4700-4717 ◽  
Author(s):  
Anup Parchure ◽  
Neha Vyas ◽  
Charles Ferguson ◽  
Robert G. Parton ◽  
Satyajit Mayor
Keyword(s):  
Cell Surface ◽  
Long Range ◽  
Imaginal Discs ◽  
Multivesicular Bodies ◽  
Selective Effect ◽  
Endosomal Sorting ◽  
Drosophila Wing ◽  
Dependent Process ◽  
Wing Imaginal Discs ◽  
Hh Signaling

Hedgehog (Hh) is a secreted morphogen involved in both short- and long-range signaling necessary for tissue patterning during development. It is unclear how this dually lipidated protein is transported over a long range in the aqueous milieu of interstitial spaces. We previously showed that the long-range signaling of Hh requires its oligomerization. Here we show that Hh is secreted in the form of exovesicles. These are derived by the endocytic delivery of cell surface Hh to multivesicular bodies (MVBs) via an endosomal sorting complex required for transport (ECSRT)–dependent process. Perturbations of ESCRT proteins have a selective effect on long-range Hh signaling in Drosophila wing imaginal discs. Of importance, oligomerization-defective Hh is inefficiently incorporated into exovesicles due to its poor endocytic delivery to MVBs. These results provide evidence that nanoscale organization of Hh regulates the secretion of Hh on ESCRT-derived exovesicles, which in turn act as a vehicle for long-range signaling.

scholarly journals Tissue repair and regeneration in Drosophila imaginal discs

2011 ◽  
Vol 53 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Ada Repiso ◽  
Cora Bergantiños ◽  
Montserrat Corominas ◽  
Florenci Serras
Keyword(s):  
Tissue Repair ◽  
Imaginal Discs ◽  
Tissue Repair And Regeneration
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