Prothoracic gland function in diapause and non-diapause Sarcophaga argyrostoma and Calliphora vicina

Richard, David; Saunders, D. S.

doi:10.1016/0022-1910(87)90016-3

Cited by 83 publications

(29 citation statements)

References 20 publications

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“…It is important to note, however, that diapause incidence was 100% in all D15 and D20 samples used in the present study, i.e. all larvae were selected after 30 days postoviposition, which denotes the start of diapause in this species (Richard and Saunders, 1987). Thus, the cold hardiness differences observed are not a consequence of differences in diapause incidence.…”

Section: Discussionmentioning

confidence: 79%

“…Thus, any subsequent variation in cold hardiness was a response to adult acclimation temperature. D and ND larvae are morphologically indistinguishable; however, D larvae can be identified as larvae not pupariating by day 30 post-oviposition (Saunders, 1987), as the larval ring gland becomes refractory to stimulation by the brain neuropeptide, prothoracicotropic hormone (Richard and Saunders, 1987). For this reason, ND larvae were collected day 15 post-oviposition, while D larvae were identified by a delayed pupariation (Saunders, 1987) and collected day 30 post-oviposition.…”

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confidence: 99%

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Cross generation plasticity in cold hardiness is associated with diapause, but not the non-diapause developmental pathway, in the blowfly, Calliphora vicina

Coleman

Bale

Hayward

2014

Journal of Experimental Biology

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Predicting insect responses to global climate change involves understanding cross-generation effects of temperature. The majority of temperate insects overwinter in a state of diapause, a pre-emptive response to winter conditions associated with increased cold hardiness. Diapause is often induced following maternal adult detection of an environmental cue signifying the onset of winter, whilst diapause is initiated in a subsequent life stage and/or generation. Continued global warming will expose adults to higher late-autumn temperatures, whilst diapause life stages will still experience prolonged winter cold. The cross-generation effect of temperature was investigated by acclimating adult Calliphora vicina to present-day (15°C) and future (20°C) late-autumn conditions and assessing cold-hardiness in diapause (D15 and D20) and nondiapause (ND15 and ND20) progeny. A cross-generation plasticity in cold hardiness was associated with D but not ND larvae. D15 larvae exhibited an enhanced ability to suppress internal freezing (supercooling point=-18.9±0.9°C) compared with D20 (−15.3±0.8°C), and displayed a greater tolerance of prolonged exposure to −4°C (LT 50 =26.0±1.0 and 11.4±1.1 days, respectively) and −8°C (5.1±1.1 and 3.0±1.1 days, respectively). These changes were associated with a reduced glucose content in D15 (2.4±0.3 g mg −1 ) compared with D20 (3.0±0.3 g mg −1) larvae. In conclusion, C. vicina adults exposed to warmer autumn conditions during diapause induction will produce larvae with a reduced cold hardiness capacity, which could negatively impact winter survival. Given that maternal regulation of diapause is common among temperate insects, this could be a widespread phenomenon. KEY WORDS: Insect, Diapause, Cross generation, Cold hardiness, Climate change INTRODUCTIONInsects residing within the temperate zone experience yearly winter cycles of low temperatures, potentially freezing conditions and limited nutrient availability. To enhance the chances of survival during this period, insects either migrate to more favourable locations, which offer sufficient resources for growth and reproduction, or remain in situ, where physiological and biochemical adaptations are implemented to assist winter survival (Tauber and Tauber, 1976;Danks, 1987;Danks, 2002). The majority of temperate insects utilise the latter approach and enter a dormant state called diapause (Denlinger and Lee, 2010). Diapause is a genetically programmed, pre-emptive response to adverse environmental RESEARCH ARTICLESchool of Biosciences, University of Birmingham, Birmingham B15 2TT, UK. conditions (Denlinger, 2002), which synchronises active life stages with more favourable conditions and enhances winter survival (Danks, 2002; Hahn and Denlinger, 2007).Diapause can be either obligatory or facultative (Tauber et al., 1986). Obligatory diapause occurs at a specific stage in the life cycle irrespective of prevailing environmental conditions, while facultative diapause is induced following detection of specific environmental cues (Denlinge...

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Section: Discussionmentioning

confidence: 79%

mentioning

confidence: 99%

Cross generation plasticity in cold hardiness is associated with diapause, but not the non-diapause developmental pathway, in the blowfly, Calliphora vicina

Coleman

Bale

Hayward

2014

Journal of Experimental Biology

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“…Thus the convention adopted for defining diapause assumed that larvae that had not pupariated by day 30 were in diapause. This limit was supported by studies at 11°C showing that the ecdysone-producing ring glands become refractory to prothoracicotropic hormone (PTTH) stimulation 26 days after hatching (Richard and Saunders, 1987). Therefore, by day 30 any nonpupariated larvae were almost certainly in diapause.…”

Section: Photoperiodic Induction Of Diapausementioning

confidence: 95%

Adult Locomotor Rhythmicity as "Hands" of the Maternal Photoperiodic Clock Regulating Larval Diapause in the Blowfly, Calliphora vicina

Kenny

Saunders

1991

J Biol Rhythms

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Some basic properties of the adult locomotor activity rhythm and of the maternal induction of larval diapause in Calliphora vicina are described. Diapause responses in Nanda-Hamner experiments indicate that circadian rhythmicity is involved in photoperiodic time measurement (PPTM). However, although the locomotor rhythm shows long-lasting changes in free-running period (aftereffects of photoperiod and constant light) and occasional "splitting," thereby indicating a structural complexity to the circadian system, the overt rhythm may be used as an indicator of phase relationships (or "hands") of the covert system involved in PPTM, within the framework of a simple external-coincidence model for the diapause clock. Thus, in light-dark (LD) cycles close to "resonance" with the circadian pacemaker(s) (T 24, LD 12:12; T 48, LD 12:36; and T 72, LD 12:60), light is restricted to the subjective day and diapause incidence is high. In T 36 (LD 12:24) and T 60 (LD 12:48), light falls into the subjective night and illuminates the postulated light-sensitive phase (phi i), and diapause incidence is low. Within the primary range of entrainment, light invades the late subjective night in T 20 (LD 12:8), illuminates phi i, and causes low incidence of diapause; however, it invades the early subjective night in T 30 (LD 12:18) and diapause remains high.

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“…In the absence of ecdysteroids from the PG, the larva fails to initiate the next molt. The failure of the brain to release ecdysteroids can usually be directly attributed to the brain’s failure to release the PTTH [35]. While a low level or an absence of JH at the end of the larval or pupal stages allows 20E to promote metamorphosis [6].…”

Section: Introductionmentioning

confidence: 99%

Larval diapause termination in the bamboo borer, Omphisa fuscidentalis

et al. 2017

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In insects, juvenile hormone (JH) and 20-hydroxyecdysone (20E) regulate larval growth and molting. However, little is known about how this cooperative control is terminating larval diapause especially in the bamboo borer, Omphisa fuscidentalis. In both in vivo and in vitro experiments, we here measured the expression levels of genes which were affected by juvenile hormone analogue (JHA: S-methoprene) and 20-hydroxyecdysone (20E) in diapausing O. fuscidentalis larvae. Corresponding mRNA expression changes in the subesophageal ganglion (SG) and prothoracic gland (PG) were evaluated using qRT-PCR. The data showed similar response patterns of JH receptor gene (OfMet), diapause hormone gene (OfDH-PBAN), ecdysone receptor genes (OfEcR-A and OfEcR-B1) and ecdysone inducible genes (OfBr-C, OfE75A, OfE75B, OfE75C and OfHR3). JHA induced the expressions of OfMet and OfDH-PBAN in both SG and PG, whereas ecdysone receptor genes and ecdysone inducible genes were induced by JHA only in PG. For 20E treatment group, expressions of ecdysone receptor genes and ecdysone inducible genes in both SG and PG were increased by 20E injection. In addition, the in vitro experiments showed that OfMet and OfDH-PBAN were up-regulated by JHA alone, but ecdysone receptor genes and ecdysone inducible genes were up-regulated by JHA and 20E. However, OfMet and OfDH-PBAN in the SG was expressed faster than OfMet and OfDH-PBAN in the PG and the expression of ecdysone receptor genes and ecdysone inducible genes induced by JHA was much later than observed for 20E. These results indicate that JHA might stimulate the PG indirectly via factors (OfMet and OfDH-PBAN) in the SG, which might be a regulatory mechanism for larval diapause termination in O. fuscidentalis.

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Prothoracic gland function in diapause and non-diapause Sarcophaga argyrostoma and Calliphora vicina

Cited by 83 publications

References 20 publications

Cross generation plasticity in cold hardiness is associated with diapause, but not the non-diapause developmental pathway, in the blowfly, Calliphora vicina

Cross generation plasticity in cold hardiness is associated with diapause, but not the non-diapause developmental pathway, in the blowfly, Calliphora vicina

Adult Locomotor Rhythmicity as "Hands" of the Maternal Photoperiodic Clock Regulating Larval Diapause in the Blowfly, Calliphora vicina

Larval diapause termination in the bamboo borer, Omphisa fuscidentalis

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