Moisture requirements were evaluated for female adults of spider beetles Mezium affine Boieldieu and Gibbium aequinoctiale Boieldieu to determine how they are differentially adapted for life in a dry environment. Features showing extreme desiccation resistance of M. affine were an impermeable cuticle wherein activation energies (43 kJ/mol) were suppressed, daily water losses as little as 0.3%/day with an associated group effect, a low 64% water content and an impressive ability to survive nearly 3 months with no food and water. Behaviorally, the extended period of water stress and fasting was marked by long intervals of physical inactivity (quiescence), as though dead. These characteristics emphasizing water retention rather than gain are shared by G. aequinoctiale and reflect a typical xerophilic water balance profile. Water uptake was restricted to imbibing liquid, as evidenced by uptake of dye-stained droplets of free water and a critical equilibrium activity of 1.00a(v), where the inability to absorb water vapor from the air fails to equilibrate declining water levels (gain not equal to loss) except at saturation. Four-fold reduction in survival time within dry air and accelerated water loss rates with high activation energies for female adults of the closely related winged Prostephanus truncatus (Say) suggest that the enhanced water conservation of spider beetles is due, in part, to fusion of their elytra supplemented by entering into quiescence.

The urban food garden is an interesting natural solution to the need to develop sponge cities structured and designed to absorb and capture rain water for reducing flooding, worldwide. This study applied a storm water management model and field experiments to investigate properties of the garden substrates. Taipei City was taken as a case study as the Taiwan government has promoted urban food garden projects since 2015. The urban food garden in Taipei has established a cultivable area of 197,168 m², 64,026 m² (32.5%) of which is designated as green-roof gardens and the rest as domestic gardens. Four substrate mixtures were found to have infiltration rates positively related to their soil water content. Substrate 1 had the highest infiltration rate (6.47 × 10⁻⁵ m/s) and soil water content (281%) when vegetation grows in limited containers. In 2019, the total water retention capacity of the urban food garden in Taipei City was 50,550.7 m³. This means that 1 m² of the urban food garden in Taipei retained 256.4 kg of water. Considering climatic conditions, the water retention capacity of the green-roof gardens in Taipei ranges from 28.2% to 41.0%. During short-term high-density rainfall events, the green-roof gardens were found to be more efficient in reducing the runoff volume, whereas during long-term high-density rainfall events, they were found to be more efficient in reducing the runoff peak flow duration (~20 mins) compared with concrete surfaces. This study proved that establishing the urban food garden contributes to increasing the water retention capacity and reducing the volume of surface runoff and the duration of runoff peak flow in prevention of flood disasters.