The incubation period lasted 5–7 days (1–7 August 2019 8 th to 14 th day). In addition, when we removed the oxygen pump, the parents started to fan the eggs attached to the substrates with continuous waves of contraction using the flanks of their bodies ( S1 Video). There were approximately 272.8☖2.9 eggs/clutch (range: 186–359 eggs/clutch, n = 10), with an average egg diameter of 452☓3 μm (range: 396–514 μm, n = 20 Fig 3A). On the third and fourth day of gestation (30–31 July 2019 6 th and 7 th day of the observation period), the leeches deposited clutches of creamy white and roundish eggs on the substrates (glass, pottery, or turtle shell) near the oxygen pump and covered them with their bellies (one-third of the way down their bodies, posterior to the venter) ( Fig 2A–2D). The gestation of creamy white eggs in both ovisacs occurred one or two days after copulation ( Fig 2A–2C).

siamensis moved toward the substrate near the oxygen pump, where they attached and remained motionless. On separation, after the last copulation, each P.

On the third day (27 July 2019), after the ten Placobdelloides siamensis individuals had fed on the snail-eating turtle (in the turtle container), with blood filling their crop ceca, repeated copulations were observed at the bottom of the container for several hours. Throughout this observation period (25 July–5 September 2019 43 days), the average water temperature in the turtle container was 30.1☑.4☌ (26.5–34.0☌).

The water temperature in both containers was measured every six hours (0000, 0600, 1200, and 1800 h) every day. Four periods were recorded: the copulation period (attachment of the posterior sucker to the substrate and body-wiping against the partner's genital pore region), incubation period (from the first egg deposition to the first hatching), parental care period (from the last hatching through the first juveniles leaving their parent), and maturation period (from the last juvenile leaving its parent for its first copulation). siamensis individuals were transferred into the turtle container for blood feeding, and their life cycles were observed. Once a week, half the water was drained from the turtle container and fresh water was added until it reached the former level this process was performed once a month for the leech container. The weight and carapace length of the turtle were recorded both pre- and poststudy, and Mazuri Aquatic Turtle Diet was provided once a day. The turtle was maintained at room temperature in a glass container (57x32x33 cm 3) that was filled one-third of the way with water a pot was placed above the water level for basking and an oxygen pump was placed in the water. siamensis, the life cycle and the duration of each growth stage of this species were examined in a laboratory. Therefore, to improve our understanding of the reproductive status of P. siamensis is adaptable to various freshwater conditions however, the life cycle of this species, and the Placobdelloides genera, is still unknown. Siamese shield leech ( Placobdelloides siamensis Oka, 1917 ) is a common freshwater glossiphoniid leech in the subfamily Glossiphoniinae that is found feeding on various Thai geoemydidae turtle species, such as Cuora amboinensis Daudin, 1802, Cyclemys oldhamii Gray, 1863, Hieremys annandalii Boulenger, 1903, Heosemys grandis Gray, 1860, Malayemys khoratensis Ihlow et al., 2016, Malayemys macrocephala Gray, 1859, Malayemys subtrijuga Schlegel & Müller, 1845, and Siebenrockiella crassicollis. Theromyzon tessulatum Müller, 1774 ) show a mixture of these characters. Helobdella stagnalis Linnaeus, 1758 and Helobdella triserialis Blanchard, 1849 ) attach cocoons directly to the venter of the parent, and monogeneric Theromyzinae (a unique genus, i.e. Glossiphonia complanata Linnaeus, 1758 ) attach cocoons to substrates, Haementeriinae (i.e. Īccording to Kutschera and Wirtz (2001), the Glossiphoniidae family can be divided into three subfamilies based on cocoon attachments: Glossiphoniinae (i.e. The parent usually covers the cocoons under its body for protection and provision of food for the developing larvae. Then, thin-walled cocoons, which consist of large yolk-filled eggs, are created.

During their reproductive activities, individuals seize a partner with their anterior portions and the two leeches exchange pseudospermatophores, which appear to release spermatozoa on the surface of their bodies. Glossiphoniid leeches are easily bred in laboratory conditions and exhibit parental care behavior, which is probably de novo in this family. Historically, glossiphoniid leeches have been favored over European medicinal leeches ( Hirudo medicinalis Linnaeus, 1758) for the study of animal development.

Leech life