How Crucial is the Functional Pit Organ for the Varroa Mite?

Olfaction as well as gustation, are essential for animal survival, allowing behavioral modulation according to environmental input. We focused our study on an obligate ecto-parasitic mite of honey bees, the Varroa destructor Anderson and Trueman (Parasitiformes, Mesostigmata, Varroidae). By mechanically blocking the main olfactory organ on Varroa forelegs by varnishing with nail polish, we were able to show that other sensory organs cannot significantly compensate chemosensory abilities required for mite’s host selection, identification as well as reproduction. In fact, we found that mites with blocked forelegs had a significantly lower ability to reach a host bee than those with varnished idiosoma and unvarnished control. Furthermore, fewer foreleg blocked mites were feeding on the nurse bees and their reproduction in the brood cells was significantly impaired. The inhibition of reproduction was also reflected in altered expression levels of vitellogenin and vitellogenin receptor genes in foreleg-blocked mites.

A new Western North Atlantic Ocean kitefin shark (Squaliformes: Dalatiidae) from the Gulf of Mexico

A new species of kitefin shark (Squaliformes; Dalatiidae) is described from the Gulf of Mexico (Western North Atlantic Ocean) based on five diagnostic features not seen on the only other known Mollisquama specimen, the holotype of Mollisquama parini Dolganov which was captured in the Eastern South Pacific Ocean. The new species, Mollisquama mississippiensis sp. nov., is distinguished from its congener by a putative pit organ located ventrally just posterior of the lower jaw margin center, photophores irregularly distributed along many areas of the body, 16 distinct ventral-abdominal photophore aggregations, and two differences associated with the dentition. Other potential distinguishing features are 10 fewer vertebrae than Mollisquama parini and six morphometric proportional differences that exceeded +/- 20% from the holotype.

Palpos labiales de Prestonia clarki (Lepidoptera, Pieridae): ultraestructura de órganos sensoriales y sensilas

Research on labial palps of Lepidoptera is scarce and requires the use of Scanning Electron Microscopy techniques. We describe and illustrate the three segments composing the labial palps of the Coliadinae butterfly Prestonia clarki, as well as the distribution of sensilla and both of palp's distinctive structures: the Reuter's sensitive patch and the Palp pit organ; in the palps, the basal segment is the longest, and the distal segment is the shortest. We found chaetic sensilla type 1 on the lateral outer surface of the segments. In the Reuter's sensitive patch and the Palp pit organ, sensilla are specialized. In a lateral internal view of the proximal section of the basal segment, Reuter's sensitive patch looks as an elongated area with hundreds of microtrichia, differentiated into three sections; the adjacent area shows fewer microtrichia of shorter length. In a longitudinal view of the distal segment, at the apex of the segment, is the bottle-shaped Palp pit organ; inside the Palp pit are coeloconic sensilla in the basal section and microtrichia in the distal one. In addition, two indeterminate types of sensilla similar to chaetic ones were found within the Palp pit; which we called chaetic sensilla types 2 and 3; chaetic sensilla type 1 are located on the edge of the Palp pit. The sensilla types and their distribution in the Palp pit agree with those described in other species of Lepidoptera.

Antennal sensilla of head of poultry shaft louse, Menopon gallinae (Phthiraptera, Insecta, Menoponidae, Amblycera)

Phthirapteran ectoparasites (lice) are very small arthropodan creature which spend their life on different mammalian and avian host body. Many morphological features of these tiny creatures are not visible under simple microscopic study and hence scanning electron microscopic (SEM) study is required for specific details. Antennal sensillum is also one of the special features located on anterior part of the head of the louse. The present study on the sample specimen of poultry louse, Menopon gallinae (Phthiraptera : Amblycera) showed presence of a small, ovoid scape and pedicel (broad cup-like structure having narrower base) seen in antennal sensilla under SEM. In addition to sensory setae, sense organ was present on terminal segment. Tuft organ contain 6/7 small peg like structure. Pit organ was also visible at the sub-terminal area of fourth segment. Presence of any structure resembling coeloconic chaemo-receptor was not observed on any flagellar sub-segment of M. gallinae.