Metamorphosis endowed the insects with properties that enabled them to conquer the Earth. It is a hormonally controlled morphogenetic process that transforms the larva into the adult. Metamorphosis appeared with the origin of wings and flight. The sesquiterpenoid juvenile hormone (JH) suppresses wing morphogenesis and ensures that metamorphosis takes place at the right ontogenetic time. This review explores the origin of insect metamorphosis and the ancestral function of JH. Fossil record shows that the first Paleozoic winged insects had (hemimetabolous) metamorphosis, and their larvae were likely aquatic. In the primitive wingless silverfish that lacks metamorphosis, JH is essential for late embryogenesis and reproduction. JH production after the embryo dorsal closure promotes hatching and terminal tissue maturation.

• MeSH
• biologická evoluce * MeSH
• biologická proměna MeSH
• hmyz * růst a vývoj   fyziologie   MeSH
• juvenilní hormony MeSH
• larva růst a vývoj   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• juvenilní hormony MeSH

Neonicotinoid insecticides are associated with a decline in the diversity and distribution of bees and wasps (Hymenoptera: Aculeata). The effects of neonicotinoids on the metamorphosis of aculeates have never been addressed in detail; however, recent evidence suggests that neonicotinoids induce wing abnormalities. We hypothesized that the metamorphosis success of bees and wasps differs in response to contact exposure to field-realistic concentrations of neonicotinoid insecticides or in response to combined exposure to neonicotinoid insecticides and benzimidazole fungicides. We treated prepupae of the model crabronid wasp Pemphredon fabricii with field-realistic concentrations of four neonicotinoids, acetamiprid, imidacloprid, thiacloprid and thiamethoxam, and/or with the benzimidazole fungicide thiabendazole. Treatment with acetamiprid or imidacloprid decreased the pupation rates to only 39% and 32%, respectively. Treatment with thiacloprid or thiamethoxam did not affect the pupation rate when applied alone, but the subsequent treatment of thiacloprid- or thiamethoxam-treated prepupae with thiabendazole led to significant decreases in pupation rates. A high concentration of acetamiprid, which severely affected the pupation rates, had moderate effects on metamorphosis into adults, resulting in 53% metamorphosis success (as opposed to 95% metamorphosis success in the water-treated group). However, imidacloprid or thiamethoxam treatment resulted in only 5%-10% metamorphosis success into adults. Overall survival decreased in response to treatment with any of the neonicotinoids or benzimidazoles or their combinations, with extremely low survival (<2%) following combined treatment with imidacloprid and thiabendazole or thiamethoxam and thiabendazole. In conclusion, neonicotinoids alter insect metamorphosis success, which can be further potentiated by their combination with other agrochemicals, such as benzimidazoles.

• MeSH
• biologická proměna účinky léků   MeSH
• insekticidy farmakologie   MeSH
• kukla růst a vývoj   MeSH
• neonikotinoidy farmakologie   MeSH
• sršňovití růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• insekticidy MeSH
• neonikotinoidy MeSH

To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.

• Klíčová slova
• developmental biology, differentiation, ecdysone, juvenile hormone, metamorphosis, myoglianin, precocene, thermobia domestica,
• MeSH
• biologická proměna * fyziologie   MeSH
• hmyz MeSH
• juvenilní hormony * MeSH
• morfogeneze MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• juvenilní hormony * MeSH

Azole fungicides have been essential pillars of global food security since the commercialization of triadimefon. However, the potential for fungicides to induce sublethal effects on larval development and emergence from overwintering is underresearched. We hypothesized that contact exposure to field-realistic concentrations of a broad spectrum of triazole fungicides alters the pupation and metamorphosis of crabronid wasps. Therefore, triazole fungicides shape the hymenopteran communities in agrocenoses. We applied field-realistic concentrations of three triazole fungicides, difenoconazole, penconazole, and tebuconazole, to the defecated prepupae of Pemphredon fabricii (Hymenoptera: Crabronidae). We monitored their survival, pupation, and metamorphosis into adults, including the timing of these events. All three tested triazole fungicides altered the time to the metamorphosis into adults of P. fabricii prepupae compared to the vehicle-treated controls. This effect was concentration-independent within the recommended concentration ranges for foliar applications. However, the three triazole fungicides were not associated with any significant declines in overall survival. Thus, the commonly used triazole fungicides affect the synchronization of the metamorphosis into adults with the availability of food and nesting resources of the study species. The study compounds did not affect the survival, which agrees with previous studies of other azole fungicides, which revealed effects on survival only when used in combination with other compounds. Further research should address the multiplicative effects of the triazole fungicides with other agrochemicals on the timing of the metamorphosis of bees and wasps.

• Klíčová slova
• Eclosion, Fungicide, Hymenoptera, Pupation, Reproduction, Sublethal effect,
• MeSH
• azoly farmakologie   MeSH
• biologická proměna MeSH
• fungicidy průmyslové * chemie   MeSH
• Hymenoptera * MeSH
• sršňovití * MeSH
• triazoly chemie   toxicita   MeSH
• včely MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• azoly MeSH
• fungicidy průmyslové * MeSH
• triazoly MeSH

The fact that calcium ions regulate the secretion of thyroid hormones could be extended to explore how the mechanisms of anuran metamorphosis is controlled by thyroid hormones. In the present study, an attempt was made to investigate the effects of both calcium channel blocker, Diltiazem (DT) and calmodulin inhibitor, Trifluoperazine (TFP) on metamorphosis and various developmental stages of the anuran tadpole, Rana tigerina. Both DT (25 microM) and TFP (2 microM) treatments caused total inhibition of the development and metamorphosis of the tadpole at premetamorphic stages. The metamorphosis was delayed by DT and totally inhibited by TFP when tadpoles were exposed at prometamorphic stages. Both drugs could not affect the tadpoles at climax stage. The findings suggest an active involvement of thyroid hormone in premetamorphic tadpoles. Calcium channel blockage with DT could not prevent the progression of tadpoles through prometamorphic stages which suggest that the change in calcium pool is not a determining factor mediating thyroid hormone release mechanism. The study suggests that in tadpole growth thyroid hormone secretion is modulated by calmodulin bound intracellular calcium.

• MeSH
• biologická proměna účinky léků   MeSH
• diltiazem farmakologie   MeSH
• kalmodulin antagonisté a inhibitory   MeSH
• larva účinky léků   růst a vývoj   MeSH
• Ranidae růst a vývoj   MeSH
• trifluoperazin farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• diltiazem MeSH
• kalmodulin MeSH
• trifluoperazin MeSH

• MeSH
• biologická proměna * MeSH
• buněčná diferenciace * MeSH
• Xenopus růst a vývoj   MeSH
• žáby MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• biologická proměna * MeSH
• hmyz fyziologie   MeSH
• neurosekreční systémy fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In conjunction with the 100th anniversary of birth of the Czech physiologist V. Laufberger who discovered in 1913 the possibility to induce metamorphosis in neotenous larvae of axolotls by feeding them with thyroid gland, the author gives an account on the development of knowledge regarding metamorphosis in amphibia. He analyzes the participation of endocrine glands, in particular thyroid hormones and prolactin. Special attention is devoted to mechanisms leading to resorption of the tail in tadpoles, i. e. the activation of lysosomal enzymes due to the action of thyroid hormones. Prolactin has an inhibitory effect on metamorphosis. An important part is obviously played by deiodination of the prohormone thyroxine in target tissues to active triiodothyronine. Recently it was demonstrated that during metamorphosis a significant role is played by apoptosis (controlled non-inflammatory absorption of superfluous cells).

• MeSH
• Ambystoma růst a vývoj   MeSH
• biologická proměna * MeSH
• dějiny 20. století MeSH
• hormony štítné žlázy fyziologie   MeSH
• Ranidae růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• dějiny 20. století MeSH
• zvířata MeSH
• Publikační typ
• anglický abstrakt MeSH
• biografie MeSH
• časopisecké články MeSH
• historické články MeSH
• Geografické názvy
• Československo MeSH
• Názvy látek
• hormony štítné žlázy MeSH

• O autorovi
• Laufberger, V

The glochidium larvae of freshwater mussels of the family Unionidae need to find suitable hosts to attach themselves and metamorphose into free-living juveniles. The specificity of the host-parasite relationship was investigated for the Iberian Unio tumidiformis Castro, 1885 by means of experimental infections and also by analyzing naturally infected fish. The process of encapsulation of glochidia was studied using scanning electron microscopy. Unio tumidiformis has proven to be an unusual host-specific unionid mussel, apparently parasitizing only fish of the genus Squalius Bonaparte, 1837. Successful encapsulation or complete metamorphosis was observed in five fish taxa: S. aradensis (Coelho, Bogutskaya, Rodrigues et Collares-Pereira), S. caroliterti (Doadrio), S. pyrenaicus (Günther), S. torgalensis (Coelho, Bogutskaya, Rodrigues et Collares-Pereira) and S. alburnoides (Steindachner) complex (only for the nuclear hybrids with at least one copy of the S. pyrenaicus genome). Complete metamorphose was achieved in 6 to 14 days at mean temperatures ranging from 21.8 to 26.1 degrees C. The current study provides support for cell migration being the main force of cyst formation and shows the influence of potential host's genome in response to the infection process to determine the success of the metamorphosis.

• MeSH
• biologická proměna fyziologie   MeSH
• epitel fyziologie   MeSH
• interakce hostitele a parazita fyziologie   MeSH
• larva růst a vývoj   fyziologie   ultrastruktura   MeSH
• mlži růst a vývoj   fyziologie   ultrastruktura   MeSH
• ryby parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Portugalsko epidemiologie   MeSH

In aquatic systems, chemical cues are one of the major sources of information through which animals can assess local predation risk. Non-native red-eared sliders (Trachemys scripta elegans) have the potential to disrupt aquatic ecosystems in Central Europe because of their superior competitive abilities and omnivorous diets. In this study, we examined whether continuous predator-borne cues are tied to changes in the developmental rates, growth rates and sizes at metamorphosis of common frog tadpoles (Rana temporaria). Our results show rather rarely documented types of amphibian prey responses to caged predators. The presence of turtles shortened the time at metamorphosis of tadpoles from 110 ± 11.7 days to 93 ± 13.0 days (mean ± S.D.). The first metamorphosed individuals were recorded on the 65th day and on the 80th day from hatching in the predator treatment and in the control group, respectively. The froglets were significantly smaller (12.8 ± 0.99 mm) in the presence of the predator than in the control treatment (15.2 ± 1.27 mm). The growth rate trajectories were similar between the predator treatment and the control. Thus, predator-induced tadpole defences were evident in higher developmental rates and smaller sizes at metamorphosis without significant changes in growth.

• MeSH
• biologická evoluce MeSH
• biologická proměna * MeSH
• ekosystém MeSH
• podněty * MeSH
• predátorské chování * MeSH
• žáby fyziologie   MeSH
• želvy fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH