Catch‐up growth in the rhinoceros beetle Trypoxylus dichotomus (Coleoptera: Scarabaeidae): Smaller neonates gain relatively more body mass during larval development

2019 ◽  
Vol 22 (4) ◽  
pp. 373-380 ◽  
Author(s):  
Sugihiko Hoshizaki
2020 ◽  
Author(s):  
Huan Yang ◽  
Chong Juan You ◽  
Clement K. M. Tsui ◽  
Luke R. Tembrock ◽  
Zhi Qiang Wu ◽  
...  

Author(s):  
Monika Weiss ◽  
Sven Thatje ◽  
Olaf Heilmayer ◽  
Klaus Anger ◽  
Thomas Brey ◽  
...  

The influence of temperature on larval survival and development was studied in the edible crab, Cancer pagurus, from a population off the island of Helgoland, North Sea. In rearing experiments conducted at six different temperatures (6°, 10°, 14°, 15°, 18° and 24°C), zoeal development was only completed at 14° and 15°C. Instar duration of the Zoea I was negatively correlated with temperature. A model relating larval body mass to temperature and developmental time suggests that successful larval development is possible within a narrow temperature range (14° ± 3°C) only. This temperature optimum coincides with the highest citrate synthase activity found at 14°C. A comparison for intraspecific variability among freshly hatched zoeae from different females (CW 13–17 cm, N = 8) revealed that both body mass and elemental composition varied significantly. Initial larval dry weight ranged from 12.1 to 17.9 μg/individual, the carbon content from 4.6 to 5.8 μg/individual, nitrogen from 1.1 to 1.3 μg/individual, and the C:N ratio from 4.1 to 4.4. A narrow larval temperature tolerance range of C. pagurus as well as the indication of intraspecific variability in female energy allocation into eggs may indicate a potential vulnerability of this species to climate change. Large-scale studies on the ecological and physiological resilience potential of this commercially fished predator are needed.


2014 ◽  
Vol 107 (2) ◽  
pp. 443-451 ◽  
Author(s):  
Byung-Ho Bang ◽  
Moon-Soo Rhee ◽  
Dong-Ho Chang ◽  
Doo-Sang Park ◽  
Byoung-Chan Kim

2014 ◽  
Vol 99 (8) ◽  
pp. 2878-2886 ◽  
Author(s):  
Ahmet Uçar ◽  
Michal Yackobovitch-Gavan ◽  
Oğuz Bülent Erol ◽  
Ensar Yekeler ◽  
Nurçin Saka ◽  
...  

Context: The causes of polycystic ovarian syndrome (PCOS) in girls with precocious adrenarche (PA) remain unclear. Objective: Our goal was to compare the clinical, biochemical, and ultrasound characteristics of girls with PA whose size at birth was appropriate for gestational age (AGA) vs those born small for gestational age (SGA). PCOS-associated metabolic and morphological correlates were examined. Design: Glucose tolerance, ACTH stimulation, and transabdominal ultrasounds were examined in 56 AGA and 31 SGA girls with PA. Bone age and hormonal profiles were determined. SGA girls were divided into 2 groups by catch-up growth (CUG) status. Subgroups were compared. Results: Chronological age, Tanner stage for pubarche, ovarian volume, and uterine volume were similar between the groups. SGA girls had lower body mass index and higher bone age-adjusted post-corticotropin cortisol. We found increased body mass index-adjusted mean serum insulin, reduced insulin sensitivity, and reduced IGF-binding protein-1 in SGA girls. Multicystic ovaries were more common in SGA girls (odds ratio [OR] = 9.69, 95% confidence interval [CI] = 3.34–28.15; P < .001). SGA girls without CUG had a higher incidence of multicystic ovaries than CUG counterparts (OR = 8.4, 95% CI = 1.4–19.3; P = .027). Being born SGA (OR = 43.4, 95% CI = 6.9–84.7; P = .001] and exaggerated 17-hydroxyprogesterone response (OR = 15.8, 95% CI = 1.7–49.8; P = .015) were associated with multicystic ovaries. Conclusions: Significant differences in hormone levels, insulin sensitivity, and ovarian maturity were found in prepubertal girls with PA who were SGA. Longitudinal follow-up will help determine whether these factors contribute to a specific PCOS phenotype in SGA girls with PA.


2014 ◽  
Vol 281 (1786) ◽  
pp. 20140696 ◽  
Author(s):  
Erin L. McCullough

The horns of giant rhinoceros beetles are a classic example of the elaborate morphologies that can result from sexual selection. Theory predicts that sexual traits will evolve to be increasingly exaggerated until survival costs balance the reproductive benefits of further trait elaboration. In Trypoxylus dichotomus , long horns confer a competitive advantage to males, yet previous studies have found that they do not incur survival costs. It is therefore unlikely that horn size is limited by the theoretical cost–benefit equilibrium. However, males sometimes fight vigorously enough to break their horns, so mechanical limits may set an upper bound on horn size. Here, I tested this mechanical limit hypothesis by measuring safety factors across the full range of horn sizes. Safety factors were calculated as the ratio between the force required to break a horn and the maximum force exerted on a horn during a typical fight. I found that safety factors decrease with increasing horn length, indicating that the risk of breakage is indeed highest for the longest horns. Structural failure of oversized horns may therefore oppose the continued exaggeration of horn length driven by male–male competition and set a mechanical limit on the maximum size of rhinoceros beetle horns.


Genomics Data ◽  
2016 ◽  
Vol 7 ◽  
pp. 301-302
Author(s):  
Yookyung Lee ◽  
Sooyeon Lim ◽  
Moon-Soo Rhee ◽  
Dong-Ho Chang ◽  
Byoung-Chan Kim

2006 ◽  
Vol 91 (11) ◽  
pp. 4645-4649 ◽  
Author(s):  
Germán Iñiguez ◽  
Ken Ong ◽  
Rodrigo Bazaes ◽  
Alejandra Avila ◽  
Teresa Salazar ◽  
...  

Abstract Introduction: Insulin resistance (IR) develops as early as age 1 to 3 yr in small for gestational age (SGA) infants who show rapid catch-up postnatal weight gain. In contrast, greater insulin secretion is related to infancy height gains. We hypothesized that IGF-I levels could be differentially related to gains in length and weight and also differentially related to IR and insulin secretion. Methods: In a prospective study of 50 SGA (birth weight < 5th percentile) and 14 normal birth weight [appropriate for gestational age (AGA)] newborns, we measured serum IGF-I levels at birth, 1 yr, and 3 yr. IR (by homeostasis model assessment) and insulin secretion (by short iv glucose tolerance test) were also measured at 1 yr and 3 yr. Results: SGA infants had similar mean length and weight at 3 yr compared with AGA infants. SGA infants had lower IGF-I levels at birth (P < 0.0001), but conversely they had higher IGF-I levels at 3 yr (P = 0.003) than AGA infants. Within the SGA group, at 1 yr IGF-I was associated with length gain from birth and insulin secretion (P < 0.0001); in contrast at 3 yr IGF-I was positively related to weight, body mass index, and IR. Conclusions: IGF-I levels increased rapidly from birth in SGA, but not AGA children. During the key first-year growth period, IGF-I levels were related to β-cell function and longitudinal growth. In contrast, by 3 yr, when catch-up growth was completed, IGF-I levels were related to body mass index and IR, and these higher IGF-I levels in SGA infants might indicate the presence of relative IGF-I resistance.


Biologia ◽  
2011 ◽  
Vol 66 (6) ◽  
Author(s):  
Pablo Grenat ◽  
Lucio Zavala Gallo ◽  
Nancy Salas ◽  
Adolfo Martino

AbstractWe provide the first description of development for a species belonging to Odontophrynus genus by describing all external changes of embryonic and larval stages for Odontophrynus cordobae. External morphological changes through development were analyzed on specimens bred in captivity. Embryonic and larval development, from fertilization to metamorphosis, was completed in 62 days and 46 stages were defined. We split the staging series into ten developmental groups: fertilization (stages 1 and 2); segmentation (stages 3–9); gastrulation (stages 10–12); neurulation (stages 13–16); elongation (stages 17–19); external gill larva (stages 20–24); internal gill larva (stage 25); pre-metamorphosis (stages 26–41); pro-metamorphosis (stage 42); metamorphic climax (stages 43–46). Marked increases in total length were evidenced during elongation and during stage 25, when the tadpole begins to feed. Stage 25 was the longest one (8 days) and it was related to organs rearrangement, morphological progression and body mass increment typical of free life larval form. Similar studies on related species are needed to compare different developmental stages at different taxonomic levels.


2022 ◽  
Author(s):  
Shinichi Morita ◽  
Tomoko F. Shibata ◽  
Tomoaki Nishiyama ◽  
Yuuki Kobayashi ◽  
Katsushi Yamaguchi ◽  
...  

Beetles are the largest insect order and one of the most successful animal groups in terms of number of species. The Japanese rhinoceros beetle Trypoxylus dichotomus (Coleoptera, Scarabaeidae, Dynastini) is a giant beetle with distinctive exaggerated horns present on the head and prothoracic regions of the male. T. dichotomus has been used as research model in various fields such as evolutionary developmental biology, ecology, ethology, biomimetics, and drug discovery. In this study, de novo assembly of 615 Mb, representing 80% of the genome estimated by flow cytometry, was obtained using the 10x Chromium platform. The scaffold N50 length of the genome assembly was 8.02 Mb, with repetitive elements predicted to comprise 49.5% of the assembly. In total, 23,987 protein-coding genes were predicted in the genome. In addition, de novo assembly of the mitochondrial genome yielded a contig of 20,217 bp. We also analyzed the transcriptome by generating 16 RNA-seq libraries from a variety of tissues of both sexes and developmental stages, which allowed us to identify 13 co-expressed gene modules. The detailed genomic and transcriptomic information of T. dichotomus is the most comprehensive among those reported for any species of Dynastinae. This genomic information will be an excellent resource for further functional and evolutionary analyses, including the evolutionary origin and genetic regulation of beetle horns and the molecular mechanisms underlying sexual dimorphism.


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