Using Visible Implant Elastomer to tag insects across life stages: a preliminary investigation with blow flies (Diptera: Calliphoridae)

Visible Implant Elastomer (VIE) has previously been used successfully to tag individuals in a variety of marine and amphibious animals, earthworms, and scorpions. Visible Implant Elastomer tags were injected into third instars of the blow fly Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) to test its compatibility and retention across life stages. Injecting into the dorsal midline of the 11th segment (seventh abdominal segment) produced survival rates of 80%, with no significant difference in the subsequent rate of development (z = 0.21, P = 0.83) as compared with untagged insects. Tags remained visible and allowed identification of individuals within a feeding, intermingling aggregation (maggot mass), especially when a high-contrast fluorescent colour was used. Tags were retained across life-stage changes and were easily found in dissected adults.

MODULI STABILIZATION IN HETEROTIC M-THEORY

We examine the stabilization of the two typical moduli, the length ρ of the 11th segment and the volume V of the internal six-manifold, in compactified heterotic M-theory. It is shown that, under certain conditions, the phenomenologically favored vacuum expectation values of ρ and V can be obtained by the combined effects of multi-gaugino condensations on the hidden wall and the membrane instantons wrapping the three-cycle of the internal six-manifold.

The largest Cambrian animal, Anomalocaris , Burgess Shale, British-Columbia

Isolated specimens of the appendage Anomalocaris canadensis have long been known; a single incomplete specimen of an animal having a pair of these appendages attached anteriorly is described. Seven dorsoventrally compressed, partly complete individuals of a similar animal that had a different pair of appendages (‘F’ of Briggs 1979) attached anteriorly are described, together with two obliquely compressed individuals that are thought to be conspecific. Surrounding the mouth of this latter species is a circlet of plates identical with the supposed medusoid coelenterate Peytoia nathorsti ; this species is referred to Anomalocaris; Laggania is a junior synonym. As now understood, Anomalocaris was an animal that reached a length of 0.5 m, the elongate body having a head region bearing one pair of large, lateral eye lobes, each borne on a short stalk, the single pair of appendages attached at the ventral, anterior margin. The 13 segments of the appendage in A. canadensis bore paired spines on the inner side, short spines on the outer side, and there was a terminal, spinose 14th segment. The appendage in A. nathorsti consisted of 11 segments, the 2nd to 10th bearing on the inner side a graduated series of spinose blades, and spines on the lateral and outer sides, the terminal 11th segment ending in a group of spines. The circlet of plates surrounding the mouth was situated ventrally on the head region immediately behind the appendages; the plates bore teeth and the circlet constituted a jaw mechanism; additional groups of spines were present in the buccal cavity. Beneath the head region, behind the mouth, were three pairs of semicircular flaps, strongly overlapping: on the tapering trunk were 11 pairs of triangular lateral lobes, widest at the mid-length of the trunk, reduced progressively in size backward. These lobes were strongly overlapping in the same sense as the flaps on the head, and attached low on the sides. The trunk termination was short and blunt, without any projecting spine or lobe. Attached to the side of the body, above each flap and lateral lobe, was a multi-lamellar structure, apparently a gill. A thin cuticle covered the head region dorsally, and ventrally around the appendages and jaw circlet, behind this becoming a lateral strip that narrowed backward. It is suggested that a thin cuticle covered the trunk region dorsally and hung down beside the gills; this covering may have been continuous, but possibly was divided into tergites. Irregular patches of apatite, and some matrix, occur in the trace of the alimentary canal, which extended to the tip of the trunk. Mineralized patches occur in association with the gills, and as transverse strips, presumed traces of some internal organ or structure. The cuticle of the appendages and jaw circlet was presumably stout, hence these parts of the body were more resistant to decay and so were preserved in isolation. The thin cuticle of the lateral lobes shows rays which were presumably thicker and strengthening in function. We suggest that this animal, the largest known from Cambrian rocks, swam by using the series of closely spaced lateral lobes essentially as a lateral fin along which waves of motion were propagated. If the waves were moved in either the same, or opposite, sense on each side, considerable manoeuvrability would have resulted. The anterior pair of appendages, and jaw mechanism, would have made Anomalocaris a formidable predator, particularly on soft-bodied benthos including the abundant arthropods without a mineralized exoskeleton. No fragments of hard parts have been observed in the gut, but there is evidence that it may have inflicted wounds on trilobites. Anomalocaris was a metameric animal, and had one pair of jointed appendages and a unique circlet of jaw plates. We do not consider it an arthropod, but the representative of a hitherto unknown phylum. It is best known from A. nathorsti , the single specimen of A. canadensis having a different appendage but the rest of the body similar, probably including the jaw circlet. The evidence is insufficient to reach any conclusion on whether or not these two 'species' may be sexual dimorphs of a single species. The single specimen of Amiella ornata is redescribed. It shows what may be lateral lobes like those of Anomalcris, but other features unlike it. We conclude that this specimen is not an example of Sidneyia inexpectans , and is too incomplete for its relationship to be determined.

The embryology of Lytta viridana LeConte (Coleoptera: Meloidae). VI. The appendiculate, 72-h embryo

The embryology of L. viridana is continued to the 72-h stage, when a little over one-quarter of the embryonic period has elapsed. The origin of the segmental appendages, further development of the coelomic sacs and enteron rudiments, formation of the nerve ganglia, appearance of tracheal invaginations, migration of the germ cells, and secretion of the serosal cuticle are described. The embryonic origin of the labrum is preoral and preantennal, that of the antennae and deutocerebrum paraoral. The tritocerebrum is formed in a well-defined intercalary segment. The ventral musculature of the stomodaeum arises from intercalary mesoderm, the dorsal and lateral musculature from labral mesoderm. The outer sheaths of the Malpighian tubules are formed from mesoderm of the 10th abdominal segment, the musculature of the proctodaeum from the 11th segment. The pleuropodia differentiate rapidly and begin secreting. The germ cell rudiment subdivides into three to six pairs of germ cell clusters, which become arranged segmentally.

A study of the development of the head and pharynx of the larval urodele Hynobius and its bearing on the evolution of the vertebrate head

The early development of the head and pharynx of Hynobius nebulosus (11.5 to 32 mm long) and retardatus (27 and 37 mm specimens) was investigated in some detail from transverse serial microtome sections. Analysis included the chondrocranium, jaws and hyobranchial skeleton, ossifications, cranial and anterior spinal nerves, musculature, blood system and other associated anatomical features. The structure of the skeletogenous elements in general agreed with earlier descriptions. However, a rudimentary fenestra lateralis nasi is found in the nasal capsule of H. nebulosus , hitherto not reported, and a complete cartilaginous processus pterygoideus, confluent with the trabecula and inner margin of the lamina orbito-nasalis described by Edgeworth (1923 a ), was not extant in any Hynobius specimen. H. retardatus has a hypoglossal foramen (and nerve) and joins H. nebulosus (Fox 1957), Cryptobranchus japonicus and alleghaniensis as the only living Amphibia to possess this structure. The neural arch homology of the occipital crest is reaffirmed. The columella stilus of the 32 mm H. nebulosus is confluent with the pterygo-quadrate cartilage and because the hyoid and columella have a common blastematous origin in Hypogeophis (Marcus 1910), it is suggested that there was an ancestral cartilaginous continuity between the hyoid and pterygo-quadrate cartilage, similar to the commissura terminales of the branchiale. This feature would further emphasize the branchial segmental homologies of the mandibular cartilage, hyoid and branchiale. The pattern of the cranial nerves is similar to that of other urodele larvae and the arrangement of the profundus and maxillaris nerves supports the view of the descent of urodeles from porolepiforme crossopterygians (Jarvik 1942). There is a segmental series of eleven head-pharynx segments, a complete branchial segment including a levator muscle, nerve, cartilage bar and gill cleft. Each post-hyoid segment is complete except for the absence of branchiale V and VI, and behind the fourth functional gill cleft there are three vestigial blind ones and then the larynx and trachea leading to the lungs. The masseter (2nd segment), digastricus (3rd segment), dilator laryngeus (10th segment) and trapezius (11th segment) are considered to be the homologues of the other six intervening levator gill arch muscles. The arytenoid and tracheal cartilages are considered to be branchial bars of the 10th and 11th segments respectively, and the lungs to have developed from gill pouches of the 11th segment which failed to reach the exterior early in vertebrate evolution. The classical view of the homology of the laryngo-tracheal skeleton with a branchial bar enunciated by Gegenbaur and Wilder independently in 1892 is therefore upheld; disagreement is merely a numerical one. The basic segmental components of the amphibian head and pharynx are modified in ontogeny by omission, distortion or addition, in order to fit the animal for a terrestrial existence.

Memoirs: On the Structure of Vermiculus pilosus

The chief characters of Vermiculus pilosus are therefore the following: Four bundles to each segment of furcate setae, generally three per bundle. A dense covering of hair-like processes. A vascular system, containing red blood, and composed of a dorsal and a ventral longitudinal vessel communicating by means of lateral vessels which branch on to the body-wall. The absence of hearts or commissural vessels. An elaborate system of unicellular valves in the longitudinal and transverse dorsal vessels. A brain deeply cleft in front, and a nerve-cord bearing muscular strands of considerable size. A compact nephridium, the funnel of which is peculiarly modified. A pair of testes in the 10th, and a pair of ovaries in the 11th segment. Two short sperm-ducts, without prostate, opening into a median chamber, which itself opens to the exterior on the 11th segment by a large median pore. Oviducts rudimentary. Two pear-shaped spermathecse, opening by a common median ventral pore on the 10th segment. An anterior and a posterior sperm-sac, and an ovisac. A clitellum extending over the 10th, 11th, 12th, and part of the 13th segments. Many of these characters place this little worm in a very isolated position. The dense covering of "sense-hairs," although perhaps of no great morphological importance, is quite unique amongst the Oligochseta. The absence of commissural vessels again distinguishes it, I believe, from all its allies, except the smallest and lowest, such as Æolosoma; nor is it usual among the Tubificidse, to which Vermiculus is doubtless related, to find strong muscular strands on the nerve-cord. As for the nephridium, the ciliated process of the funnel is no doubt of the same nature as the long ciliated processes on the nephridiostome of Nereis (3);1 all such structures appear to be specialised processes of the funnel-cells themselves. The presence of cilia in special ampullæ, and their absence in the rest of the nephridial canal, is a character which may, I think, prove to be common to all the so-called Microdrili. Such ampullæ are certainly present in other Tubificids I have examined, and in the Enchytræids, to the nephridium of which latter the compact excretory organ of Vermiculus bears no little resemblance. Professor Vejdovsky (6) has described a Planarian, Microplana humicola, in which the nephridia terminate in flame-cells, while the canal itself is provided with "flames" at intervals along its course ; it seems not improbable that the flame-like cilia of the nephridiostome of Vermiculus represent the "flame" of the terminal cell, and the cilia of the ampullae represent the "flames" distributed along the course of the canal in the Planarian. Possibly the arrangement found in the large nephridia of the Earthworms, described by Benham (1), in which whole tracts are ciliated, is derived from some such system as we find in Vermiculus and the lower Oligochaetes by the extension of the cilia over a great length of the canal.1 The late development of the median spermiducal chamber is another of those characters quite peculiar to our worm. What the function of this chamber may be it is difficult to conjecture; perhaps it acts as a sucker during copulation; the disposition of the muscles would favour this supposition. However, it must be noticed that besides the formation of the spermiducal chamber, the apertures of the genital organs themselves show a distinct tendency, as it were, to unite in the middle line. This is clearly seen in the case of the male pores, which come close to each other; but more especially in the case of the spermathecal pores, which become actually confluent. As a striking contrast, we may compare such a form as Heterochseta, in which, as described by Benham (2), the sperm-ducts and spermathecae open above the ventral setse! The fact that Bothrioneuron, described by Stole (5), possesses a median male pore might suggest a close relationship between the two worms, but they differ in other particulars most markedly from each other. The setse, nervous system, and nephridia of Bothrioneuron are all very different from those of Vermiculus; it possesses commissural vessels, a prostate, a complicated system of genital setse, and no spermathecee. On the whole, it must be concluded that Vermiculus stands very much by itself; the shaæ of its setas, and above all the situation of its gonads, place it in the family Tubificidae, but its more intimate relationships remain obscure for the presewt.

NOTES ON THE EARLY STAGES OF SOME MOTHS

Larva, I example–Body smooth, thick and uniform to the 11th segment, from which it tapers abruptly to the end. Cinnamon brown; a large sub-dorsal, velvety, dark brown shade on the 4th, 5th and 11th rings, and on each of the remaining rings, except the three first and last one, is a dorsal curved line, and two small roundish spots of the same color; two larger, square, dark brown dorsal spots edged with yellowish-white, on the first ring.Head roundish, as wide as the body.