Potamyia flavata

Larval gut contents in Potamyia flavata in seven sampling sites Larval gut contents were assessed qualitatively. Contents were separated into diatoms, green algae, filamentous algae, arthropod fragments, and detritus. Gut content analysis indicated that larvae are omnivorous filterers. The predominant items were diatoms and green algae followed by filamentous algae, detritus, and arthropod fragments (Fig. 25). Biology and habitat The specimens were found in small and medium streams in the Phachi watershed, western Thailand, at altitudes between 123 and 220 m asl. The streams have moderately clean and slightly warm water. The annual temperature range at this site is between 26.30 – 29.83 ° C (Prommi, in press). The majority of larvae and pupae were collected in stream sections where the flows run past villages and agricultural areas. The larvae were found on substrate consisting of cobbles, pebbles, and gravel with relatively moderate – fast running waters. They construct a typical hydropsychid fixed tubular retreat with a silken filter net at the entrance, in which larvae capture small food items. The pupae were found abundantly in more slowly flowing water, with shelters firmly attached to rocks. Based on collecting data of the studied material, Po. flavata has multiple generations per year.

Sumber: The larva and pupa of Potamyia flavata (Banks 1934) (Trichoptera: Hydropsychidae): Description, life cycle, and notes on its biology

Larva: Total length 9.5 – 10.5 mm (n = 10). C-shape body typical for Hydropsychidae. Background color of head and notal sclerites yellow. Head: Head capsule width 0.80 – 1.15 mm (n = 10). Entire head light yellow (Figs. 2 – 4). Frontoclypeus with anterior margin concave, slightly crenulate; faint large spot anteromedially; pair of faint light marks immediately anterior of tentorial pits and faint light mark between them; posteromedian portion with one pair of small, pale, muscle scars and small cluster of muscle scars near posterior apex (Fig. 5). Region around eyes and posterior quarter of head lighter yellow in dorsal view (Fig. 3), ventral side darker along midline (Fig. 4). Head covered with long setae, mingled with tapered setae on dorsal and lateral regions in anterior three-quarters (Fig. 3). Labrum light-brown; elliptical in dorsal view; bearing dense and well-developed, brown setae anterolaterally and setae on dorsal surface, posterior margin slightly concave in middle (Fig. 6). Mandibles with prominent lateral flanges, each with row of setae along lateral groove. Each mandible with 2 apical and 4 mesal teeth, right mandible with basal tooth distant from others, left mandible with mesal tuft of hairs (Fig. 7). Submentum trapezoidal with posterolateral and anterolateral corners broadly rounded; anterior margin broadly Y-shaped with median cleft; cleft with sides parallel; lateral areas with setae (Fig. 8). Anterior ventral apotome without or with weakly prominent anteromedian tubercle, lateral arms long, narrow, apically blunt, and posterior point acute; posterior ventral apotome small (Figs. 4, 8). Thorax: Nota yellow with covering of brown setae. Pronotum covered with long, truncate peg setae, mingled with tapered setae, same setae projecting beyond anterior margin (Figs. 9 – 10). Meso- and metanota each covered with numerous, inclined, long, scale hairs; same setae projecting beyond anterior margin (Figs. 9, 11 – 12). Prosternite broadly transverse, with broad dark band along posterior margin and with pair of small sclerites near posterolateral angles (Fig. 16). Propleura ventrally with stout setae; foretrochantins unforked and each with rudimentary basodorsal ramus (Fig. 13). Forelegs with feather-like setae mingled with palmate setae on mesal and lateral surfaces of coxae; trochanters and femora with long, feather-like setae on ventral surfaces mingled with long setae (Fig. 13). Mid- and hind legs similar in size, shape, and structure; each with feather-like setae mingled with spike-like setae on posterior surface of trochanter, femur, and tibia (Figs. 14 – 15). Mesosternum with one pair of gills; metasternum with 2 pairs of gills; gills consisting of central stem bearing many lateral filaments (Fig. 2). Abdomen: Abdominal segments with long, recumbent setae, more dense ventrally. (Figs. 2, 9, 17 – 18). First sternum with 2 pairs of gills with adjacent bases (Figs. 2, 9). Segments II – V each with one pair of median gills. Segments II – VII each with one pair of lateral gills each arising from common base. Sterna VIII and IX each with pair of spike-bearing plates, sternum IX with spikes emanating from prominent sockets. Each sclerite of sternum IX entire posteriorly and triangular. Tergum IX with small lateral sclerite and pair of large ventral sclerites (Fig. 17). Anal prolegs with bent apicoventral claw and apicodorsal cluster of long bristles, dorsal surfaces with spikelike setae, ventral surfaces without spike-like setae (Figs. 2, 18). Pupa (Figs. 19 – 22): Mandibles tapering regularly to pointed apex; inner margin with 4 large teeth (Fig. 20); widened basally, with elongate setae on lateral and ventral surfaces. Dorsally, with 1 pair of anterior hook plates on each of abdominal segments III – VIII; 1 pair of posterior hook plates on each of segments III – IV (Figs. 19, 21 – 22), posterior hook plates of segment IV covered with row of long setae (Fig. 21). Apical processes each with wide base narrowing distally to subapicolateral shoulder; apex obliquely truncate; ventral surface and lateral margins bearing long setae (Fig. 22).

Sumber: The larva and pupa of Potamyia flavata (Banks 1934) (Trichoptera: Hydropsychidae): Description, life cycle, and notes on its biology

Larval instars of Potamyia flavata Larval, pupal, and adult specimens were collected on all occasions during February, May, and December 2015 and revealed a multivoltine life cycle. The larvae were classified into five instars using 2,133 specimens. Head widths of first instars ranged from 0.20 to 0.29 mm (n = 22). Head widths of second instars ranged from 0.30 to 0.39 mm (n = 143), of third instars from 0.40 to 0.59 mm (n = 491), of fourth instars from 0.60 to 0.79 mm (n = 1,404) and of fifth instars from 0.80 to 1.15 mm (n = 73) (Fig. 23). Temporal distribution of larval instars varied among sampling sites (Fig. 24). First instar larvae were absent from sampling sites PC 1, PC 4, PC 7, and PC 8 at all sampling times, whereas the second to the fifth instar larvae were found. Also, second instar larvae were not collected from sampling sites PC 4 and PC 8. Most third instar larvae were found at sampling site PC 3, fourth instar larvae were present at sampling site PC 7, whereas most fifth instar larvae were collected at sampling site PC 8. All instar larvae were found at sampling sites PC 3 and PC 6.

Sumber: The larva and pupa of Potamyia flavata (Banks 1934) (Trichoptera: Hydropsychidae): Description, life cycle, and notes on its biology

Southeast Asia harbors the highest diversity of Trichoptera on the planet (Schmid 1984; Morse 2016). However, most taxonomic studies have focused on adults. As a consequence, very few taxonomic studies have addressed the immature stages which, ironically, are more important from a water quality perspective. Clearly, more descriptions of larval morphology and biology are needed to enable a refined understanding of the benthic fauna in southeast Asian streams.

Sumber: The larva and pupa of Potamyia flavata (Banks 1934) (Trichoptera: Hydropsychidae): Description, life cycle, and notes on its biology

Redescription. Overall color in alcohol pale yellowish, maxillary and labial palps pale. Head yellowish, antennae pale yellowish, legs pale. Body covered with scattered light golden pubescence. Wings pale, membranes faint brown, with pale maculation and reticulate pattern. Length from tip of head to apices of folded forewings about 7.10 mm (n = 12). Length of each forewing 6.00 mm. Length of each hind wing 4.25 mm. Male genitalia (Figs 12 – 16). In lateral view (Fig. 12), abdominal segment IX annular, anteriorly convex, narrower both dorsally and ventrally; apical lobe on posterolateral margin well developed, subtriangular and apically round. In lateral view (Fig. 12), body of tergum X very short, quadrangular; hooked dorsad in apical 1 / 3; in dorsal view almost quadrangular, apically forming triangular setose lobes; interlobular gap very small and V-shaped; setose areas well defined (probably mesal setose lobes) with variably long setae. Inferior appendages each two-segmented, in lateral and ventral views (Figs 12, 14) basal segment slender and curved slightly dorsad sub-basally, thicker and curved posterad apically; apical segment thick and directed mesad, with fine hook visible apically in both lateral (Fig. 12) and dorsal views. In lateral view, (Fig. 15) phallic apparatus broad basally, narrow in middle, distal apex slightly upcurving; in ventral view (Fig. 16) ventral subapical keel short and broad; phallotremal sclerite small, in lateral view (Fig. 15) horizontal and situated dorsally, following upcurving endothecal process.

Sumber: New records of Hydropsychinae (Insecta: Trichoptera: Hydropsychidae) from Assam, India

Distribution. China (Hainan, Tibet), Vietnam, Malaysia, Thailand, Indonesia (Sumatra, Java, Bali, Lombok), India (Assam).

Sumber: New records of Hydropsychinae (Insecta: Trichoptera: Hydropsychidae) from Assam, India