Life History Characteristics
67
Mediterranean arthropods inhabit environments where seasonal predictability dominates over hazardous fluctuations of environmental variables.
Nonetheless, as indicated, energy for reproduction is unevenly allocated
among the different age groups. Younger and, to a lesser extent, older adults
contribute more to reproduction than specimens in intermediate life stages,
and relevant graphs display first and second order peaks. Dispersion of
reproductive effort among the age groups can be considered to be an adaptation· to spatially heterogeneous Mediterranean habitats. Moreover, slightly
distributing the reproductive effort over time can equally be viewed as an
adaptation to minor climatic hazards and can be effective in response to
unpredictable anthropogenic impacts. Thus, in accordance with Norton
(1994), it can be concluded that Mediterranean arthropods compensate precocity and small clutch size with elements of a "bet-hedging" reproductive
strategy such as long adult life, low adult mortality, and slight dispersion of
reproductive effort over time, which can be considered buffers against environmental disasters.
5.1.3.3
Parental Care
Parental investment, which is linked to the survival of subsequent instars, is
seen in most Mediterranean arthropods. Brood protection is common among
arthropods from a variety of habitats. For example, Bercovitz and Warburg
(1985) observed this phenomenon in the millipede A. t. judaicus and Matthiessen (1991) in the white-fringed weevil G. leucoloma.
Brood protection among Mediterranean arthropods involves adaptations
either to predation or to drought. Relevant to the former is the fact that the
eggs of oribatids and collembolans can escape the attention of hungry predators when deposited in small holes (Stamou and Asikidis 1992). Adaptations to summer drought appear to be even more significant. Apart from anatomical structures such as the marsupium in isopods, relevant adaptations
can also be observed in ethology. Crawford et al. (1987) reported that maternally formed pellets surround diplopod eggs and early stages of development in
both mesic and xeric Mediterranean areas. The eggs of most Mediterranean
diplopods are deposited in specific chambers made either exclusively of
faeces or a mixture of faecal, humic and mineral materials. Egglaying chambers presumably to some extent protect eggs from desiccation. Moreover, batches of diplopod eggs are laid in the vicinity of sites where favourable hygric
conditions prevail (Baker 1978a; Bercovitz and Warburg 1988; Iatrou 1989).
Similarly, most oribatids and collembolans lay their eggs on moss leaves
where evapotranspiration can protect them from desiccation, while the eggs
of other arthropods are laid among fallen leaves or lichen tissues.
Indirect energy allocation of another type by deceased mothers to their
offspring has been described in the woodlouse S. tiberianum from Israeli
67
Mediterranean arthropods inhabit environments where seasonal predictability dominates over hazardous fluctuations of environmental variables.
Nonetheless, as indicated, energy for reproduction is unevenly allocated
among the different age groups. Younger and, to a lesser extent, older adults
contribute more to reproduction than specimens in intermediate life stages,
and relevant graphs display first and second order peaks. Dispersion of
reproductive effort among the age groups can be considered to be an adaptation· to spatially heterogeneous Mediterranean habitats. Moreover, slightly
distributing the reproductive effort over time can equally be viewed as an
adaptation to minor climatic hazards and can be effective in response to
unpredictable anthropogenic impacts. Thus, in accordance with Norton
(1994), it can be concluded that Mediterranean arthropods compensate precocity and small clutch size with elements of a "bet-hedging" reproductive
strategy such as long adult life, low adult mortality, and slight dispersion of
reproductive effort over time, which can be considered buffers against environmental disasters.
5.1.3.3
Parental Care
Parental investment, which is linked to the survival of subsequent instars, is
seen in most Mediterranean arthropods. Brood protection is common among
arthropods from a variety of habitats. For example, Bercovitz and Warburg
(1985) observed this phenomenon in the millipede A. t. judaicus and Matthiessen (1991) in the white-fringed weevil G. leucoloma.
Brood protection among Mediterranean arthropods involves adaptations
either to predation or to drought. Relevant to the former is the fact that the
eggs of oribatids and collembolans can escape the attention of hungry predators when deposited in small holes (Stamou and Asikidis 1992). Adaptations to summer drought appear to be even more significant. Apart from anatomical structures such as the marsupium in isopods, relevant adaptations
can also be observed in ethology. Crawford et al. (1987) reported that maternally formed pellets surround diplopod eggs and early stages of development in
both mesic and xeric Mediterranean areas. The eggs of most Mediterranean
diplopods are deposited in specific chambers made either exclusively of
faeces or a mixture of faecal, humic and mineral materials. Egglaying chambers presumably to some extent protect eggs from desiccation. Moreover, batches of diplopod eggs are laid in the vicinity of sites where favourable hygric
conditions prevail (Baker 1978a; Bercovitz and Warburg 1988; Iatrou 1989).
Similarly, most oribatids and collembolans lay their eggs on moss leaves
where evapotranspiration can protect them from desiccation, while the eggs
of other arthropods are laid among fallen leaves or lichen tissues.
Indirect energy allocation of another type by deceased mothers to their
offspring has been described in the woodlouse S. tiberianum from Israeli