scholarly journals Dispersal of Phraortes illepidus (Phasmida: Phasmatidae) Eggs by Workers of the Queenless Ant, Pristomyrmex punctatus (Hymenoptera: Formicidae)

Sociobiology ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. e7194
Author(s):  
Yoshiyuki Toyama ◽  
Izuru Kuroki ◽  
Keiji Nakamura
Keyword(s):  
Host Plants ◽  
Stick Insect ◽  
Ant Nests ◽  
Stick Insects ◽  
Interspecific Relation ◽  
Place Of Origin ◽  
Slow Moving ◽  
Pristomyrmex Punctatus ◽  
Queenless Ant

Eggs of some stick insects bear external appendages called capitula. Foraging worker ants attracted by capitula disperse eggs in a response similar to the responses of workers to elaiosome-bearing seeds of many plants. For this study, we conducted rearing experiments in the laboratory to elucidate the interspecific relation between the queenless ant, Pristomyrmex punctatus Smith, and the stick insect, Phraortes illepidus (Brunner von Wattenwyl) of which eggs bear capitula. Eggs of P. illepidus were proposed to P. punctatus in the laboratory. Capitula were removed from most of the eggs not only when ants were starved but also when ants were well-fed. In large rearing containers, eggs were transported by ants from their place of origin. Many eggs were transferred horizontally on the surface. Although some eggs were found in the artificial ant nests, it is likely that stick insects are not in active ant nests at the time of hatching in nature because of P. punctatus nest-moving habits. The percentage of eggs buried in the sand was small. Furthermore, most of the buried eggs were found at less than 3 cm depth. Results show that many P. illepidus hatchlings can reach host plants safely without being attacked by ant workers. These results suggest that P. punctatus can be a good partner of P. illepidus. Ants disperse eggs of slow-moving stink insects in exchange for some nutrition from capitula.

Extensive chromosome variation in the stick insect genus Sipyloidea Brunner von Wattenwyl (Phylliidae : Necrosciinae) within Australia, and descriptions of three new species

1987 ◽  
Vol 1 (6) ◽  
pp. 603 ◽  
Author(s):  
B John ◽  
DCF Rentz ◽  
N Contreras
Keyword(s):  
New Species ◽  
Host Plants ◽  
Geographical Area ◽  
Morphological Characteristics ◽  
Stick Insect ◽  
Chromosome Counts ◽  
Chromosome Variation ◽  
Stick Insects ◽  
Parthenogenetic Reproduction ◽  
Three New Species

Combined cytological and morphological analyses of stick insects belonging to the genus Sipyloidea Brunner from a limited geographical area in southern and south-western Australia serve to identify three new species, designated as the Nelida group. All three live on species of Acacia and are nocturnal, with micropterous females but fully winged males. Bisexual members of S. nelida, sp. nov., are characterised by 2n = 37 male XO, 38 female XX, but females with counts of 58 XX, 57 XX and 69 XX, 68 XX have been identified within the species. A second species, S. similis, sp. nov., has bisexual forms with 2n = 35 male XO, 36 female XX, as well as females with counts of 58 XX or 57 XX. In both species the females with the higher chromosome counts are capable of parthenogenetic reproduction. Both deposit their eggs under the bark of host plants and shortly after oviposition these liberate a ring of stellate hairs around the opercular region of the egg. The third species, S. ovabdita, sp. nov., is apparently purely bisexual with 2n = 35 male XO, 36 female XX. It is distinctive in its morphological characteristics from both S. nelida and S. similis and lays its eggs in soil, lacking the opercular ring of hairs which characterises the other two species.

scholarly journals Correction - Extensive chromosome variation in the stick insect genus Sipyloidea Brunner von Wattenwyl (Phylliidae : Necrosciinae) within Australia, and descriptions of three new species

1987 ◽  
Vol 1 (6) ◽  
pp. 603
Author(s):  
B John ◽  
DCF Rentz ◽  
N Contreras
Keyword(s):  
New Species ◽  
Host Plants ◽  
Geographical Area ◽  
Morphological Characteristics ◽  
Stick Insect ◽  
Chromosome Counts ◽  
Chromosome Variation ◽  
Stick Insects ◽  
Parthenogenetic Reproduction ◽  
Three New Species

Combined cytological and morphological analyses of stick insects belonging to the genus Sipyloidea Brunner from a limited geographical area in southern and south-western Australia serve to identify three new species, designated as the Nelida group. All three live on species of Acacia and are nocturnal, with micropterous females but fully winged males. Bisexual members of S. nelida, sp. nov., are characterised by 2n = 37 male XO, 38 female XX, but females with counts of 58 XX, 57 XX and 69 XX, 68 XX have been identified within the species. A second species, S. similis, sp. nov., has bisexual forms with 2n = 35 male XO, 36 female XX, as well as females with counts of 58 XX or 57 XX. In both species the females with the higher chromosome counts are capable of parthenogenetic reproduction. Both deposit their eggs under the bark of host plants and shortly after oviposition these liberate a ring of stellate hairs around the opercular region of the egg. The third species, S. ovabdita, sp. nov., is apparently purely bisexual with 2n = 35 male XO, 36 female XX. It is distinctive in its morphological characteristics from both S. nelida and S. similis and lays its eggs in soil, lacking the opercular ring of hairs which characterises the other two species.

Intersegmental Coordination of Walking Movements in Stick Insects

2005 ◽  
Vol 93 (3) ◽  
pp. 1255-1265 ◽  
Author(s):  
Björn Ch. Ludwar ◽  
Marie L. Göritz ◽  
Joachim Schmidt
Keyword(s):  
Motor Pattern ◽  
Central Pattern Generators ◽  
Stick Insect ◽  
Neural Mechanisms ◽  
Chordotonal Organ ◽  
Adjacent Segment ◽  
Body Segments ◽  
Stick Insects ◽  
Pattern Generators ◽  
Leg Movements

Locomotion requires the coordination of movements across body segments, which in walking animals is expressed as gaits. We studied the underlying neural mechanisms of this coordination in a semi-intact walking preparation of the stick insect Carausius morosus. During walking of a single front leg on a treadmill, leg motoneuron (MN) activity tonically increased and became rhythmically modulated in the ipsilateral deafferented and deefferented mesothoracic (middle leg) ganglion. The pattern of modulation was correlated with the front leg cycle and specific for a given MN pool, although it was not consistent with functional leg movements for all MN pools. In an isolated preparation of a pair of ganglia, where one ganglion was made rhythmically active by application of pilocarpine, we found no evidence for coupling between segmental central pattern generators (CPGs) that could account for the modulation of MN activity observed in the semi-intact walking preparation. However, a third preparation provided evidence that signals from the front leg's femoral chordotonal organ (fCO) influenced activity of ipsilateral MNs in the adjacent mesothoracic ganglion. These intersegmental signals could be partially responsible for the observed MN activity modulation during front leg walking. While afferent signals from a single walking front leg modulate the activity of MNs in the adjacent segment, additional afferent signals, local or from contralateral or posterior legs, might be necessary to produce the functional motor pattern observed in freely walking animals.

Pathological and Microbiological Study of Mortality in a Captive Breeding Colony of the Endangered Lord Howe Island Stick Insect (Dryococelus australis)

2018 ◽  
Vol 55 (5) ◽  
pp. 719-730
Author(s):  
Christine Bayley ◽  
Christina Cheng ◽  
Michael Lynch
Keyword(s):  
Captive Breeding ◽  
Positive Culture ◽  
Opportunistic Pathogen ◽  
Stick Insect ◽  
Innate Immune ◽  
Breeding Colony ◽  
Lord Howe Island ◽  
Stick Insects ◽  
Gross Lesions ◽  
Increased Susceptibility

The authors describe pathological and microbiological features of mortalities in a captive breeding colony of Lord Howe Island stick insects ( Dryococelus australis) over a period of 18 months. There were 2 peaks of mortality in this period. In the first, insects presented dead with minimal premonitory signs of illness. In the second, affected insects were ataxic with contracted limbs and inability to climb or right themselves. Gross lesions were uncommon but included pigmented plaques on the gut and cloacal prolapse. Histological lesions in both outbreaks indicated a cellular innate immune response including nodulation characterized by Gram-negative bacterial bacilli entrapped within nodules of pigmented hemocytes, and melanization characterized by melanin within hemocyte nodules and around bacteria. Hemolymph culture findings varied and often yielded a mixed growth. Pure growth of Serratia marcescens was cultured in 44% of animals in Outbreak 1, while pure growth of Pseudomonas aeruginosa was cultured in 30% of animals in Outbreak 2. Cases with S. marcescens-positive culture often showed inflammation at the foregut-midgut junction. The frequency of mixed bacterial culture results did not allow firm conclusions about causality to be made, and may indicate primary bacterial infection or increased susceptibility to hemolymph colonization with an opportunistic pathogen. These findings highlight the utility of histopathology combined with ancillary testing when investigating mortality in captive insect colonies.

scholarly journals Descending octopaminergic neurons modulate sensory-evoked activity of thoracic motor neurons in stick insects

2019 ◽  
Vol 122 (6) ◽  
pp. 2388-2413 ◽  
Author(s):  
Thomas Stolz ◽  
Max Diesner ◽  
Susanne Neupert ◽  
Martin E. Hess ◽  
Estefania Delgado-Betancourt ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Stick Insect ◽  
Neuron Activity ◽  
Sense Organs ◽  
Descending Neurons ◽  
Walking Activity ◽  
Stick Insects ◽  
Evoked Activity ◽  
Sensory Evoked ◽  
Stimulation Of

Neuromodulatory neurons located in the brain can influence activity in locomotor networks residing in the spinal cord or ventral nerve cords of invertebrates. How inputs to and outputs of neuromodulatory descending neurons affect walking activity is largely unknown. With the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and immunohistochemistry, we show that a population of dorsal unpaired median (DUM) neurons descending from the gnathal ganglion to thoracic ganglia of the stick insect Carausius morosus contains the neuromodulatory amine octopamine. These neurons receive excitatory input coupled to the legs’ stance phases during treadmill walking. Inputs did not result from connections with thoracic central pattern-generating networks, but, instead, most are derived from leg load sensors. In excitatory and inhibitory retractor coxae motor neurons, spike activity in the descending DUM (desDUM) neurons increased depolarizing reflexlike responses to stimulation of leg load sensors. In these motor neurons, descending octopaminergic neurons apparently functioned as components of a positive feedback network mainly driven by load-detecting sense organs. Reflexlike responses in excitatory extensor tibiae motor neurons evoked by stimulations of a femur-tibia movement sensor either are increased or decreased or were not affected by the activity of the descending neurons, indicating different functions of desDUM neurons. The increase in motor neuron activity is often accompanied by a reflex reversal, which is characteristic for actively moving animals. Our findings indicate that some descending octopaminergic neurons can facilitate motor activity during walking and support a sensory-motor state necessary for active leg movements. NEW & NOTEWORTHY We investigated the role of descending octopaminergic neurons in the gnathal ganglion of stick insects. The neurons become active during walking, mainly triggered by input from load sensors in the legs rather than pattern-generating networks. This report provides novel evidence that octopamine released by descending neurons on stimulation of leg sense organs contributes to the modulation of leg sensory-evoked activity in a leg motor control system.

Load Signals Assist the Generation of Movement-Dependent Reflex Reversal in the Femur–Tibia Joint of Stick Insects

2006 ◽  
Vol 96 (6) ◽  
pp. 3532-3537 ◽  
Author(s):  
Turgay Akay ◽  
Ansgar Büschges
Keyword(s):  
Time Course ◽  
Stick Insect ◽  
Motor Output ◽  
Chordotonal Organ ◽  
Frequency Of Occurrence ◽  
Stick Insects ◽  
Extensor Motoneuron ◽  
Motoneuron Activity ◽  
First Time ◽  
Stimulation Of

Reinforcement of movement is an important mechanism by which sensory feedback contributes to motor control for walking. We investigate how sensory signals from movement and load sensors interact in controlling the motor output of the stick insect femur–tibia (FT) joint. In stick insects, flexion signals from the femoral chordotonal organ (fCO) at the FT joint and load signals from the femoral campaniform sensilla (fCS) are known to individually reinforce stance-phase motor output of the FT joint by promoting flexor and inhibiting extensor motoneuron activity. We quantitatively compared the time course of inactivation in extensor tibiae motoneurons in response to selective stimulation of fCS and fCO. Stimulation of either sensor generates extensor activity in a qualitatively similar manner but with a significantly different time course and frequency of occurrence. Inactivation of extensor motoneurons arising from fCS stimulation was more reliable but more than threefold slower compared with the extensor inactivation in response to flexion signals from the fCO. In contrast, simultaneous stimulation of both sense organs produced inactivation in motoneurons with a time course typical for fCO stimulation alone, but with a frequency of occurrence characteristic for fCS stimulation. This increase in probability of occurrence was also accompanied by a delayed reactivation of the extensor motoneurons. Our results indicate for the first time that load signals from the leg affect the processing of movement-related feedback in controlling motor output.

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