Ditaxis biseriata (Westwood, 1852)

Dorey, James B & Merritt, David J, 2017, First observations on the life cycle and mass eclosion events in a mantis fly (Family Mantispidae) in the subfamily Drepanicinae, Biodiversity Data Journal 5, pp. 21206-21206 : 21206

Ditaxis biseriata (Westwood, 1852)

Materials

Type status: Other material. Occurrence: catalogNumber: JD1DB ; recordedBy: James B Dorey; individualCount: 1; lifeStage: adult; associatedMedia: http://www.jamesdoreyphotography.com.au/Nonpublic-galleries/Mantispids/n-s3NpJH/; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificName: Ditaxisbiseriata; kingdom: Animalia; phylum: Arthropoda; class: Insecta; order: Neuroptera; family: Mantispidae; genus: Ditaxis; Location: country: Australia; stateProvince: New South Wales; locality: Newrybar ; verbatimElevation: 11 m; locationRemarks: label transliteration: "Newrybar, NSW, 28˚43'52.0"S 153˚33'18.8"E, J.B.Dorey, 05/09/2015, JD1DB"; verbatimCoordinates: 28˚43'52.0"S 153˚33'18.8"E; decimalLatitude: -28.731111; decimalLongitude: 153.555222; georeferenceProtocol: label; Identification: identifiedBy: Kevin Lambkin; dateIdentified: 2017; Event: samplingProtocol: sweeping; Record Level: language: en; collectionID: JD1DB; collectionCode: Insects; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence: catalogNumber: JD2DB ; recordedBy: James B Dorey; individualCount: 1; lifeStage: adult; associatedMedia: http://www.jamesdoreyphotography.com.au/Nonpublic-galleries/Mantispids/n-s3NpJH/; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificName: Ditaxisbiseriata; kingdom: Animalia; phylum: Arthropoda; class: Insecta; order: Neuroptera; family: Mantispidae; genus: Ditaxis; Location: country: Australia; stateProvince: New South Wales; locality: Newrybar ; verbatimElevation: 11 m; locationRemarks: label transliteration: "Newrybar, NSW, 28˚43'52.0"S 153˚33'18.8"E, J.B.Dorey, 05/09/2015, JD2DB"; verbatimCoordinates: 28˚43'52.0"S 153˚33'18.8"E; decimalLatitude: -28.731111; decimalLongitude: 153.555222; georeferenceProtocol: label; Identification: identifiedBy: Kevin Lambkin; dateIdentified: 2017; Event: samplingProtocol: sweeping; Record Level: language: en; collectionID: JD2DB; collectionCode: Insects; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence: catalogNumber: JD3DB ; recordedBy: James B Dorey; individualCount: 1; lifeStage: adult; associatedMedia: http://www.jamesdoreyphotography.com.au/Nonpublic-galleries/Mantispids/n-s3NpJH/; Taxon: taxonID: urn:lsid:biosci.ohio-state.edu:osuc_names:275502; scientificName: Ditaxisbiseriata; kingdom: Animalia; phylum: Arthropoda; class: Insecta; order: Neuroptera; family: Mantispidae; genus: Ditaxis; Location: country: Australia; stateProvince: New South Wales; locality: Newrybar ; verbatimElevation: 11 m; locationRemarks: label transliteration: "Newrybar, NSW, 28˚43'52.0"S 153˚33'18.8"E, J.B.Dorey, 05/09/2015, JD3DB"; decimalLatitude: -28.731111; decimalLongitude: 153.555222; georeferenceProtocol: label; Identification: identifiedBy: Kevin Lambkin; dateIdentified: 2017; Event: samplingProtocol: As pharat adult; Record Level: language: en; collectionID: JD3DB; collectionCode: Insects; basisOfRecord: PreservedSpecimen

Description

A description of the subject of this study, Ditaxis biseriata , is provided by Lambkin (1986).

Diagnosis

Ditaxis biseriata was distinguished from its sister species, Ditaxis meridiei , by characters of the adult vertex and colouration of the sclerites ( Lambkin 1986).

Distribution

The observation and collection site used in this study is within the distribution area described by Lambkin (1986), which covers the east coast of Queensland and north-east coastal region of New South Wales, Australia.

Biology

Pharate adults and eclosion behavior

The location within the orchard with the highest density of D. biseriata is wetter and has a more complete canopy then the rest of the orchard and is close to a 30-year old regenerated rainforest patch. Evening observations in early September found between one and five D. biseriata eclosing on most trees, while later in September very few were found, indicating that the mass eclosion is probably restricted to a few weeks of the year. Upon searching, eclosing adults were found in the regenerated rainforest patch near the Macadamia orchard, but at much lower densities.

Pharate adults (Fig. 1) were first observed walking upward on tree-trunks soon after sunset and would continue to appear for several hours, but in progressively lower numbers. Adult eclosion took place on tree trunks at heights that varied from ground level to approximately 2 m. Some individuals were observed to eclose on the ground or even on a camera tripod. The few individuals that eclosed on the ground appeared to be smaller than average. Pharate adults that were removed and placed on the ground would resume movement up a nearby tree to eclose. The adults are approximately 21 mm long, measured from head to tip of abdomen.

Four steps in the process of eclosion are depicted in Fig. 2 and a timelapse video of eclosion of a single adult is shown in Fig. 5. At eclosion, pharate adults stopped moving and began to pump and flex their abdomen. The pupal cuticle split along the thoracic midline and the adult’s thorax and head emerged with the head flexed ventrally. Once the head and legs were drawn free, the adult body rotated backwards over the pupal case, remaining attached to the pupal case at the posterior abdomen. Then the adult reached forward, grasped the tree trunk with all legs and moved ahead a few steps to completely free its body from the pupal case. The adult then released the grasp of the fore-legs and flexed backwards at the thorax-abdomen junction so that the head and thorax were held horizontally while the abdomen remained vertical, holding to the tree-trunk via the 2nd and 3rd pairs of legs. The prothoracic legs were retracted into the typical mantid-like position. The wings expanded and progressively became transparent in all but the pigmented sections. This wing clarification initiated proximally and proceeded to the distal wingtips. When it was almost complete, the adult straightened at the thorax-abdomen junction to adopt the typical adult posture and the wings transitioned from a splayed arrangement to the typical adult tent-like arrangement. If mechanically disturbed or exposed to flash photography before the abdominal peristalsis movements were initiated, pharates would not eclose. However, once peristaltic movements were initiated, they would complete eclosion. Predation of the newly-eclosed, immobile adults by spiders or ants was occasionally observed. Few adults were observed at the study site other than those that had just eclosed, possibly due to adults flying away from the site or into the canopy.

Eggs and first instar larvae

An adult female collected on 5th September 2015 laid c. 120 eggs attached to the lid of a petri dish two days after collection. The lime-green eggs, each c. 0.83 mm long, were deposited in a cluster suspended on a cord of diffuse silken threads (Fig. 3). Upon hatching at 12 days after deposition, larvae clung to the egg cluster for a period (Fig. 3) before dropping to the bottom of the petri dish. They were then able to climb up and out of the petri dish and wander, dropping to the ground whenever they encountered a ledge. When larvae were introduced to loose soil they would burrow into it.

The larvae are campodeiform, approximately 2 mm long, generally unsclerotised and creamy-white to light brown in colour. The mouthparts and parts of the head capsule are lightly sclerotized. The head capsule is longer than it is broad with distinctive prognathous mouthparts and anteriorly-directed antennae and labial palps (Fig. 4). The ipsilateral mandibles and maxillae combine to form paired piercing/sucking components projecting anteriorly. In life, they are generally held together along the midline.

The larval antennae are 3-segmented with a lobed terminal segment (Fig. 4). Multiple sensilla are present on the antennae including a pair of terminal sensilla extending from the tip of each distal antennomere. The terminal segment of each labial palp narrows distally to form a finger-like terminal projection. No stemmata were distinguishable in cleared specimens, and no pigmentation associated with stemmata could be seen in living specimens or in uncleared specimens stored in ethanol.