Early life-history stages of the olive barb, Systomus sarana (Hamilton), and a key ontogenetic systematic character of Smiliogastrinae.

The current study aims to uncover the early life-history stages of Systomus sarana, a medium-sized smiliogastrin cyprinid important for aquaculture in South Asia. The fish were effectively bred in captivity by administering 0.25 mL of breeding hormone per kilogram of fish. The spawning occurred 8.54 ± 0.55 h after the injection, and the eggs were phyto-lithophilic with a pale yellow color and a diameter of 1.49 ± 0.04 mm. Hatching occurred 17 h after fertilization, and the yolk-sac larvae of 3.43 ± 0.08 mm total length (TL) were adhering to the plant parts and other substrata with the cement glands on the forehead. On the third day, with complete absorption of the yolk sac and the disappearance of the attachment organ, the pre-flexion larvae measured 5.3 ± 0.11 mm TL. On the eighth day, the flexion larvae measured 6 ± 0.4 mm TL with a well-inflated posterior swim bladder, and the post-flexion larvae, at 11 days post-hatching (dph), developed a two-chambered gas bladder. The juvenile stage, on day 21 post-hatching, was marked by the loss of the median finfolds and the appearance of black blotches on the caudal, subdorsal, and supra-anal regions. The commencement of squamation and the appearance of the rudiments of maxillary barbels distinguished the juvenile stage. The subadults measuring 4.6 ± 0.36 cm TL had finished squamation and completely lost the subdorsal and supra-anal blotches. We propose that the presence of subdorsal blotches is a distinctive ontogenetic and systematic feature of larval and juvenile forms of smiliogastrin barbs.

Parasitic behavior and developmental morphology of Mesocomys trabalae (Hymenoptera: Eupelmidae), a promising parasitoid of the Japanese giant silkworm Caligula japonica (Lepidoptera: Saturniidae).

The egg parasitoid Mesocomys trabalae Yao, Yang, and Zhao is used as a biocontrol agent against the emerging defoliator pest Caligula japonica Moore in East Asia. It has been proven that the eggs of Antheraea pernyi Guérin-Méneville can be used as a factitious host for the mass production of M. trabalae. We examined the parasitic behavior and morphological characteristics of the developmental stages of M. trabalae reared on A. pernyi eggs. The parasitic behavior of M. trabalae encompasses 10 steps, involving searching, antennation, locating the oviposition site, drilling, probing, detecting, oviposition, host feeding, grooming, and resting, with the oviposition step further divided into 3 stages. We determined that the parasitoid released an egg during the second stage of the oviposition step, while her body remained in a relatively static state. Among all the steps in parasitic behavior, probing occupied the longest time, accounting for 26.33% of the entire parasitism process. It was followed by oviposition (15.88%), drilling (15.10%), antennation (13.09%), detecting (10.79%), host feeding (10.02%), and the remaining steps, each occupying less than 5.00% of the total time in steps. The pre-emergence of adult M. trabalae comprised of 4 stages: egg (0-1 day), larva (2-6 days), prepupa (7-11 days), pupa (12-20 days), followed by the development into an adult, and it usually took 20-22 days to develop from an egg into an adult at 25°C. This study advances our understanding of the biology of Mesocomys parasitoids and their mass-rearing for use in augmentation programs.

Manipulating nest architecture reveals three-dimensional building strategies and colony resilience in honeybees.

Form follows function throughout the development of an organism. This principle should apply beyond the organism to the nests they build, but empirical studies are lacking. Honeybees provide a uniquely suited system to study nest form and function throughout development because we can image the three-dimensional structure repeatedly and non-destructively. Here, we tracked nest-wide comb growth in six colonies over 45 days (control colonies) and found that colonies have a stereotypical process of development that maintains a spheroid nest shape. To experimentally test if nest structure is important for colony function, we shuffled the nests of an additional six colonies, weekly rearranging the comb positions and orientations (shuffled colonies). Surprisingly, we found no differences between control and shuffled colonies in multiple colony performance metrics-worker population, comb area, hive weight and nest temperature. However, using predictive modelling to examine how workers allocate comb to expand their nests, we show that shuffled colonies compensate for these disruptions by accounting for the three-dimensional structure to reconnect their nest. This suggests that nest architecture is more flexible than previously thought, and that superorganisms have mechanisms to compensate for drastic architectural perturbations and maintain colony function.

Platyfish bypass the constraint of the caudal fin ventral identity in teleosts.

BACKGROUND: The caudal fin of teleosts is characterized by dorsoventral symmetry. Despite this external morphology, the principal rays of this appendage connect to bones below the notochord, indicating the ventral (hypochordal) identity of this organ. RESULTS: Here, we report that this typical architecture of the caudal fin is not fully conserved in the platyfish (Xiphophorus maculatus) and the guppy (Poecilia reticulata), representatives of the Poeciliidae family. We show that in these species, 3-4 principal rays connect to bones above the notochord, suggesting an epichordal contribution. Consistently, as examined in platyfish, dorsal identity genes zic1/4 were highly expressed in these rays, providing molecular evidence of their epichordal origin. Developmental analysis revealed that the earliest rays above the notochord emerge at the 10-ray stage of fin morphogenesis. In contrast to zebrafish and medaka, platyfish and guppies display a mirrored shape of dorsal and ventral processes of the caudal endoskeleton. Our study suggests that an ancestral bauplan expanded in poeciliids by advancing its symmetrical pattern. CONCLUSION: The platyfish evolved a fin architecture with the epichordal origin of its upper principal rays and a high level of symmetry in the caudal endoskeleton. This innovative architecture highlights the adaptation of the teleost skeleton.

Comparative growth in the olfactory system of the developing chick with considerations for evolutionary studies.

Despite the long-held assumption that olfaction plays a relatively minor role in the behavioral ecology of birds, crown-group avians exhibit marked phylogenetic variation in the size and form of the olfactory apparatus. As part of a larger effort to better understand the role of olfaction and olfactory tissues in the evolution and development of the avian skull, we present the first quantitative analysis of ontogenetic scaling between olfactory features [olfactory bulbs (OBs) and olfactory turbinates] and neighboring structures (cerebrum, total brain, respiratory turbinates) based on the model organism Gallus gallus. The OB develops under the predictions of a concerted evolutionary model with rapid early growth that is quickly overcome by the longer, sustained growth of the larger cerebrum. A similar pattern is found in the nasal cavity where the morphologically simple (non-scrolled) olfactory turbinates appear and mature early, with extended growth characterizing the larger and scrolled respiratory turbinates. Pairwise regressions largely recover allometric relationships among the examined structures, with a notable exception being the isometric trajectory of the OB and olfactory turbinate. Their parallel growth suggests a unique regulatory pathway that is likely driven by the morphogenesis of the olfactory nerve, which serves as a structural bridge between the two features. Still, isometry was not necessarily expected given that the olfactory epithelium covers more than just the turbinate. These data illuminate a number of evolutionary hypotheses that, moving forward, should inform tradeoffs and constraints between the olfactory and neighboring systems in the avian head.

Growing tiny eyes: How juvenile jumping spiders retain high visual performance in the face of size limitations and developmental constraints.

Adult jumping spiders are known for their extraordinary eyesight and complex, visually guided behaviors, including elaborate communicatory displays, navigational abilities, and prey-specific predatory strategies. Juvenile spiders also exhibit many of these behaviors, yet their visual systems are many times smaller. How do juveniles retain high visually guided performance despite severe size constraints on their visual systems? We investigated developmental changes in eye morphology and visual function in the jumping spider Phidippus audax using morphology, histology, ophthalmoscopy, and optical measurements. We find that juvenile spiders have proportionally larger lenses in relation to their body size than adults. This should alleviate some of the costs of small body size on visual function. However, photoreceptor number in the anterior lateral eyes (ALE) remains constant from early development onward, consistent with a developmental constraint on photoreceptor differentiation. To accommodate these photoreceptors within the diminutive volume of the spiderling cephalothorax, ALE rhabdoms in early life stages are more tightly packed and significantly smaller in diameter and length, properties that expand across development. Lens focal lengths increase as eyes and retinas grow, resulting in a remarkable maintenance of ALE spatial acuity and field-of-view across life stages. However, this maintenance of acuity comes at a sensitivity cost given the small rhabdomal volumes required by space constraints early in life. Taken together, our results indicate that young jumping spiders have eyes already equipped for high acuity vision, but these young spiders may struggle to perform visually demanding behaviors in low-light environments, a notion that warrants further testing.

Surgical resection of large encephalocele: a report of two cases and consideration of resectability based on developmental morphology.

INTRODUCTION: The first-line treatment of encephalocele is reduction of herniated structures. Large irreducible encephalocele entails resection of the lesion. In such case, it is essential to ascertain preoperatively if the herniated structure encloses critical venous drainage. CASE REPORTS: Two cases of encephalocele presenting with large occipital mass underwent magnetic resonance (MR) imaging. In first case, the skin mass enclosed the broad space containing cerebrospinal fluid and a part of occipital lobe and cerebellum. The second case had occipital mass harboring a large portion of cerebrum enclosing dilated ventricular space. Both cases had common venous anomalies such as split superior sagittal sinus and high-positioned torcular herophili. They underwent resection of encephalocele without subsequent venous congestion. We could explain the pattern of venous anomalies in encephalocele based on normal developmental theory. CONCLUSION: Developmental theory connotes that major dural sinuses cannot herniate into the sac of encephalocele. Irrespective to its size, encephalocele can be resected safely at the neck without subsequent venous congestion.

Rare events in earth history include the LB1 human skeleton from Flores, Indonesia, as a developmental singularity, not a unique taxon.

The original centrally defining features of "Homo floresiensis" are based on bones represented only in the single specimen LB1. Initial published values of 380-mL endocranial volume and 1.06-m stature are markedly lower than later attempts to confirm them, and facial asymmetry originally unreported, then denied, has been established by our group and later confirmed independently. Of nearly 200 syndromes in which microcephaly is one sign, more than half include asymmetry as another sign and more than one-fourth also explicitly include short stature. The original diagnosis of the putative new species noted and dismissed just three developmental abnormalities. Subsequent independent attempts at diagnosis (Laron Syndrome, Majewski osteodysplastic primordial dwarfism type II, cretinism) have been hampered a priori by selectively restricted access to specimens, and disparaged a posteriori using data previously unpublished, without acknowledging that all of the independent diagnoses corroborate the patent abnormal singularity of LB1. In this report we establish in detail that even in the absence of a particular syndromic diagnosis, the originally defining features of LB1 do not establish either the uniqueness or normality necessary to meet the formal criteria for a type specimen of a new species. In a companion paper we present a new syndromic diagnosis for LB1.

Morphological constraints in children's spoken language comprehension: a visual world study of plurals inside compounds in English.

Many previous studies have shown that the human language processor is capable of rapidly integrating information from different sources during reading or listening. Yet, little is known about how this ability develops from child to adulthood. To gain insight into how children (in comparison to adults) handle different kinds of linguistic information during on-line language comprehension, the current study investigates a well-known morphological phenomenon that is subject to both structural and semantic constraints, the plurals-in-compounds effect, i.e. the dislike of plural (specifically regular plural) modifiers inside compounds (e.g. rats eater). We examined 96 seven-to-twelve-year-old children and a control group of 32 adults measuring their eye-gaze changes in response to compound-internal plural and singular forms. Our results indicate that children rely more upon structural properties of language (in the present case, morphological cues) early in development and that the ability to efficiently integrate information from multiple sources takes time for children to reach adult-like levels.