392
11.3.6 Gut Contents
Gut contents in insects assume a variety of forms, ranging from solid contents such
as pollen and indigestible plant-tissue fragments in guts of insects (Krassilov et al.
1997; Rasnitsyn and Krassilov 2000), to shaft fragments of bird feathers and vertebrate blood (Wappler et al. 2004; Greenwalt et al. 2013; Greenwalt 2021) in parasites and parasitoids. The 48 million-year-old Messel Formation of Germany
preserves gut contents spectacularly well, an example of which are butterfly scales
in the gut of the bat Palaeochiropteryx tupaiodon (Fig. 11.1i) described by Richter
and Storch (1980). Another instance is the chewing louse Saurodectes vrsanskyi
(?Phthiraptera: Saurodectidae) that shows fluidized gut contents consisting of likely
secreted dermal fluids or blood (Fig. 11.1h). For parasites, the detection of blood in
gut contents is especially important (Greenwalt 2021).
Four studies have used the gut contents in a louse, a bug, a flea and a mosquito to
indicate the presence of parasitism and reveal the specific diets of these parasites.
First, a bird louse (Phthiriaptera: Amblycera: Menoponidae), with mandibulate
mouthparts typical for this clade, was discovered among a well-preserved middle
Eocene (44 Ma) biota at Eckfeld, Germany (Wappler et al. 2004). The presence of
remains of keratinous scales from feather shaft bases in the gut of the louse, detected
by light-microscope imaging, securely indicated an ectoparasitic relationship with a
bird (Wappler et al. 2004). A second study involved bugs (Hemiptera: Heteroptera)
from the Early Cretaceous (125 Ma) Yixian Formation of northeastern China (Yao
et al. 2014). This study established Torirostratus pilosus (Hemiptera: Torirostratidae)
as closely related to Cimicidae (bed bugs) and Polyctenidae (bat bugs). An energydispersive X-ray spectroscopic examination of the head, antennae, prothorax, metathoracic leg, central abdomen and adjacent mudstone matrix (the latter used as a
standard), revealed elevated iron content, and hence the presence of degraded hemoglobin, from an opaque region in the central abdomen (Yao et al. 2014). In a third
study, a Mesozoic-aspect female flea with a substantially distended abdomen was
examined from the same deposit as the example immediately above. The flea,
Pseudopulex tanlan (Siphonaptera: Pseudopulicidae), a member of an extinct, midMesozoic lineage related to modern fleas (Huang 2014), had a ballooned abdomen
with stretched intersegmental membranes that contained 15 times the volumetric
intake of blood as that of modern fleas (Gao et al. 2014). This attribution of blood
as the cause of abdominal distension was based on the taxonomic affinity of fleas
rather than a chemical analysis. In the last study, a fossil mosquito (Diptera:
Culicidae) was discovered in the 44 million-year-old middle Eocene Kishenehn
Formation of southwestern Montana, and subsequently analyzed for a large opaque
residue in its moderately distended abdomen. Energy-dispersive X-ray spectroscopy and time-of-flight secondary ion mass spectrometry indicated that hemoglobin
was present in the mosquito’s abdomen (Greenwalt et al. 2013). While these studies
can identify with remarkable accuracy the diet of a parasite’s last meal—whether
keratin flakes from bird feather shafts or vertebrate blood—the precise species identification of the hosts of the last meal remain mostly unknown.
C. C. Labandeira and L. Li
11.3.6 Gut Contents
Gut contents in insects assume a variety of forms, ranging from solid contents such
as pollen and indigestible plant-tissue fragments in guts of insects (Krassilov et al.
1997; Rasnitsyn and Krassilov 2000), to shaft fragments of bird feathers and vertebrate blood (Wappler et al. 2004; Greenwalt et al. 2013; Greenwalt 2021) in parasites and parasitoids. The 48 million-year-old Messel Formation of Germany
preserves gut contents spectacularly well, an example of which are butterfly scales
in the gut of the bat Palaeochiropteryx tupaiodon (Fig. 11.1i) described by Richter
and Storch (1980). Another instance is the chewing louse Saurodectes vrsanskyi
(?Phthiraptera: Saurodectidae) that shows fluidized gut contents consisting of likely
secreted dermal fluids or blood (Fig. 11.1h). For parasites, the detection of blood in
gut contents is especially important (Greenwalt 2021).
Four studies have used the gut contents in a louse, a bug, a flea and a mosquito to
indicate the presence of parasitism and reveal the specific diets of these parasites.
First, a bird louse (Phthiriaptera: Amblycera: Menoponidae), with mandibulate
mouthparts typical for this clade, was discovered among a well-preserved middle
Eocene (44 Ma) biota at Eckfeld, Germany (Wappler et al. 2004). The presence of
remains of keratinous scales from feather shaft bases in the gut of the louse, detected
by light-microscope imaging, securely indicated an ectoparasitic relationship with a
bird (Wappler et al. 2004). A second study involved bugs (Hemiptera: Heteroptera)
from the Early Cretaceous (125 Ma) Yixian Formation of northeastern China (Yao
et al. 2014). This study established Torirostratus pilosus (Hemiptera: Torirostratidae)
as closely related to Cimicidae (bed bugs) and Polyctenidae (bat bugs). An energydispersive X-ray spectroscopic examination of the head, antennae, prothorax, metathoracic leg, central abdomen and adjacent mudstone matrix (the latter used as a
standard), revealed elevated iron content, and hence the presence of degraded hemoglobin, from an opaque region in the central abdomen (Yao et al. 2014). In a third
study, a Mesozoic-aspect female flea with a substantially distended abdomen was
examined from the same deposit as the example immediately above. The flea,
Pseudopulex tanlan (Siphonaptera: Pseudopulicidae), a member of an extinct, midMesozoic lineage related to modern fleas (Huang 2014), had a ballooned abdomen
with stretched intersegmental membranes that contained 15 times the volumetric
intake of blood as that of modern fleas (Gao et al. 2014). This attribution of blood
as the cause of abdominal distension was based on the taxonomic affinity of fleas
rather than a chemical analysis. In the last study, a fossil mosquito (Diptera:
Culicidae) was discovered in the 44 million-year-old middle Eocene Kishenehn
Formation of southwestern Montana, and subsequently analyzed for a large opaque
residue in its moderately distended abdomen. Energy-dispersive X-ray spectroscopy and time-of-flight secondary ion mass spectrometry indicated that hemoglobin
was present in the mosquito’s abdomen (Greenwalt et al. 2013). While these studies
can identify with remarkable accuracy the diet of a parasite’s last meal—whether
keratin flakes from bird feather shafts or vertebrate blood—the precise species identification of the hosts of the last meal remain mostly unknown.
C. C. Labandeira and L. Li