Embryonic Development and Eclosion Season of New Species Berastagia (Lepidoptera: Pyralidae) from Taiwan

This paper describes a new species of the snout moth Berastagia tainanica sp. nov. (Lepidoptera: Pyralidae) from Taiwan. From 2009 to 2016, a biology study was conducted on population dynamics and embryonic development. Spring season is the peak of the eclosion of overwintering larvae or pupae. The average longevity of adult was 14.8 ± 6.2 days (N = 174), the average number of eggs laid was 259 ± 3 eggs/moth (N = 2), the hatching rate of eggs was 95.4% (N = 262), and the average hatching time of eggs was 99.6 ± 18.6 hours (N = 68). The average body length of males was 5.64 mm ± 0.91 mm (N = 30), and the average body length of females was 6.28 mm ± 0.84 mm (N = 30). This finding indicates that female snout moths are larger than males (Global R = 0.058, P = 0.012). The snout moth eclosion rate was 16.9 moths/100 pods in the first year (2010/2011, N = 2,224 pods) and 10.9 moths/100 pods in the second year (2014/2015, N = 6,382 pods). The pod borer rate was 31.8% (N = 707) and the seed borer rate was 41.2% (N = 3,628) in the first year, whereas the pod borer rate was 76.2% (N = 6,382) in the second year.

Matrix metalloproteinase 2 contributes to adult eclosion and immune response in the small hive beetle,Aethina tumida

During the pupal-adult eclosion process of holometabolous insects,the old cuticle is shed and replaced by a completely different new cuticle that requires tanning and expansion,along with extensive extracellular matrix(ECM)remodeling.In vertebrates,matrix metalloproteinases(MMPs),a class of zinc-dependent endopeptidases,play key roles in regulating the ECM that surrounds cells.However,little is known about these extracellular proteinases available in insects.The small hive beetle(SHB),Aethina tumida,is a widespread invasive parasite of honey bees.In this study,6 MMP homologs were identified in the SHB genome.RNA interference experiments showed that all 6 AtMmps are not required for the larval-pupal transition,only AtMmp2 was essential for pupal-adult eclosion in SHB.Knockdown of AtMmp2 resulted in eclosion defects and wing expansion failure,as well as mortality within 3 d of adult eclosion.Transcriptomic analysis revealed that knockdown of AtMmp2 significantly increased expression of the Toll and Imd pathways,chitin metabolism,and cross-linking(such as the pro-phenoloxidase activating cascade pathway and the tyrosine-mediated cuticle sclerotization and pigmentation pathway).These data revealed evolutionarily conserved functions of Mmp2 in controlling adult eclosion and wing expansion,also provided a preliminary exploration of the novel function of regulating Toll and Imd pathways,as well as new insights into how MMPs regulate insect development and defense barriers.

Effects of Sodium Cyclohexyl Sulfamate on Growth and Development of Drosophila melanogaster

[Objectives]This study was conducted to investigate the effects of different concentrations of sodium cyclohexyl sulfamate on the growth and development of Drosophila melanogaster.[Methods]Different concentrations of sodium cyclohexyl sulfamate were added to the culture medium,and the effects of different concentrations of sodium cyclohexyl sulfamate on the development time and weight of D.melanogaster in various life stages were statistically analyzed.[Results]High concentration of sodium cyclohexyl sulfamate delayed the time of pupation and eclosion of D.melanogaster,which made D.melanogaster lose weight.The number of male D.melanogaster in the first generation was much larger than that of female individuals,which indicated that the effect of sodium cyclohexyl sulfamate on male D.melanogaster was greater than that of female individuals.In a word,high concentration of sodium cyclohexyl sulfamate significantly inhibited the growth and development of D.melanogaster.[Conclusions]This study provides some reference data for the research perspective of food additives and the safe use of sodium cyclohexyl sulfamate.

Foldable Units and Wing Expansion of the Oakleaf Butterfly During Eclosion

Eclosion is a rapid process of morphological changes in insects,especially for the wings of butterflies.The orange oakleaf butterfly(Kallima inachus)transits from pupae to adults with a 9.3 fold instant increase in the surface area of their wings.To explore the mechanism for the rapid morphological changes in butterfly wings,we analyzed changes in microstructures in the wings of K.inachus.We found that there were lots of micron-sized foldable units in the wings at the pupal stage.The foldable units could provide as much as 31.35 times of increase in wing surface area.During eclosion,foldable units were flattened sequentially and resulted in a rapid increase in wing surface areas.The unfolding process was regulated by the structures and layouts of wing veins.Based on our observation,foldable units play important roles in both deformation and stretching of wings.The foldable units of microstructures may provide mimics for simulating entities of large-deformational bionic structures with practical application.

Observation on Behavior of Chilades pandava

Chilades pandava is a dangerous insect pest of Cycas spp.,which seriously threatens the growth and development of Cycas plants.On the basis of previous studies,the paper summarized the behaviors of different insect states of C.pandava,such as feeding,flying,resting,mating,spawning,hatching,pupation,eclosion,etc.,in order to provide a reference for effective prevention and control of C.pandava.

Functional analysis of the circadian clock gene timeless in Tribolium castaneum

Circadian rhythms are endogenous oscillations with a period of about 24 h driven by a circadian clock. So far, variable oscillators have been found in insects. To explore the circadian clock of Tribolium castaneum, we cloned the clock gene timeless （Tctimeless）. Its open reading frame is 3240 bp in length and consists of 10 exons. Tctimeless＇ is highly expressed in the late pupal stage. Tissue-specific expression analysis in late adult stages revealed high expression of Tctimeless in the head, epidermis, fat body and accessory glands. Silencing of Tctimeless by RNA interference （RNAi） at the late larval stages caused a failure to initiate eclosion. Tctimeless knockdown in late pupal stages led to a gender-independent decline in egg production and progeny survival. As a core clock gene, Tctimeless exhibited one expression peak in the middle of the circadian day. Knockdown of Tctimeless disrupted daily expression patterns of Tccycle, Tcclock, Tcperiod and itself, while Tctimeless and Tcperiod expression patterns over the circadian day were also perturbed when Tccycle or Tcclock is suppressed by RNAi. This study identified a complex transcriptional relationship among circadian clock genes in T. castaneum.

CRISPR/Cas9-based knockout reveals that the clock gene timeless is indispensable for regulating circadian behavioral rhythms in Bombyx mori

Circadian rhythms,which are ubiquitous and adaptive,occur across all species,from microbes to humans,in which they organize and modify behavior and physiology.timeless(im)is a canonical clock gene.The core composition of the Drosophila melanogaster endogenous circadian clock has been extensively investigated;however,in lepidopteran insects,including Bombyr mori,the mechanism is complicated and little is known regarding the participation of tim in the negative feedback loop responsible for behavioral activities.To arrive at a comprehensive understanding of the role of tim in the B.mori endogenous circadian clock,we exploited the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9 gene editing system.We attermpted to elucidate the functions of tim in the circadian clock of B.mori using Bmtim mutants.The knockouts affected two circadian behavioral activities:adult emergence and embryo hatching rhythms.Quantitative real-time polymerase chain reaction results confirmed that tim-knockouts induced relative reductions in the expression levels,and thereby the oscillation amplitudes,of Bmper and Bmclk messenger RNAs during both the photophase and scotophase.Additionally,the daily rhythmic expression of Bmndbt was up-regulated in the photophase and downregulated in the scotophase in a tim-knockout.Our study reveals that tim is integral to the B.mori circadian clock and may be involved in regulating eclosion and hatching rhythms.