An "aquatic" millipede from a Central Amazonian inundation forest

Area of Science:

• Ecology
• Zoology
• Environmental Science

Background:

• Black-water inundation forests experience prolonged annual flooding (5-6 months).
• Millipedes, like Gonographis adisi (Diplopoda), inhabit these dynamic environments.
• Understanding species' adaptations to extreme environmental conditions is crucial for conservation.

Purpose of the Study:

• To investigate the flood tolerance and survival strategies of Gonographis adisi immatures.
• To determine the physiological mechanisms enabling survival during inundation periods.
• To elucidate the life-cycle adaptations of this millipede species to seasonal flooding.

Main Methods:

• Field observations in a black-water inundation forest near Manaus.
• Laboratory experiments to determine maximum flood tolerance of immatures.
• Measurement of dissolved oxygen uptake via cutaneous respiration.

Main Results:

• Advanced juvenile stages and subadults of Gonographis adisi survive 5-6 month floods under submerged tree bark.
• Millipedes graze on algae and exhibit cutaneous respiration, with high dissolved oxygen uptake (>10 μl/mg dry weight/h).
• Maximum laboratory flood tolerance for immatures reached 11 months; adults do not survive inundation.

Conclusions:

• Gonographis adisi exhibits significant adaptations for surviving prolonged annual floods, primarily in its immature stages.
• Cutaneous respiration and shelter-seeking behavior are key survival strategies during inundation.
• The life cycle is synchronized with flood patterns, with reproduction occurring during non-inundation periods.